I've certainly seen that money comes easier if there is a direct, obvious-even-to-bureacrats short-term application of the proposed work. However, I've seen people raise funds for general research in some fairly esoteric areas, too.
I think cephalopod researchers actually have one edge in a historical result: Hodgkin and Huxley's squid giant axon work led directly to the model of action potential propogation in the axons of neurons (in other words, into our understanding of how electrical "spike" signals move along the long "wiring" in the nervous system). This has had a huge impact on modern neurobiology, neurology, and probably even neuropharmacology and psychiatry. I believe that this work is approximately as fundamental to neuroscience, including human neuroscience, as the fruit fly work that won a nobel prize for its contribution to genetics was. I think it's important to be able to emphasize in fund-raising that often the study of "purely academic interest" topics can actually tell us a lot about things that we're very interested in for practical reasons.
I also find cephalopod biology in particular interesting in the "big picture" for several reasons, which I think carry over to possibilities for making major contributions to our understanding of general principles which cold have enormous implications for biology and medicine.
The thing I find the most exciting and which I believe has the most potential for great rewards from the study of cephalopods is the fact that, unlike most of the "smart" animals we study, cephalopods have evolved their nervous systems on a completely independent branch of the evloutionary tree. I have heard the claim (and although it's hard to quantify this, it seems about right) that an octopus, for example, is about as smart as a cat. Now, while there are a fair number of critters that are about as smart as a cat, pretty much all of them are vertebrates, and have some evolutionary history like fish -> invertebrates -> lizards -> mammals or some such. You just don't see a lot of jellyfish and starfish and lobsters that have a lot in the "smarts" department (bees, arguably, have some amount of intelligence, but I think it's a lot more specialized and probably hard-wired rather than learned, flexible, and reasoned). Cephalopods, on the other hand, are demonstrably intelligent on par with most mammals, and yet our most common ancestor was clearly something with almost no nervous system at all, like a limpet or sea squirt or something. Remember, ammonites and the like ruled the sea before the teleost fishes evolved-- cephalopods were swimming around before anything with a spinal cord arose at all!
This is often brought up in a very limited scope in the context of cephalopod eyes specifically-- they are mentioned as "convergent evolution" in that our common ancestor probably had eyes more primative than even nautilus (and probably more primative than a snail), yet both vertebrates and cephalopods evolved eyes that share things like adjustable pupils, clear lenses, sealed eyeballs, etc. In the scope of the eye, a lot can be learned by comparing where these separate evolutionary processes made the same "choices," and where they differ. For example, human eyes are actually, possibly due to a quirk of evolution in which choice was "locked in" because it was genetically hard to change, backwards-- the light has to pass through a layer of support neurons before it gets to the photoreceptors of the retina. Octopus eyes don't have this weirdness-- the photoreceptors are on the outside layer, closest to the pupil side, so the light hits them directly. The arrangement of photoreceptors is also different; octopus eyes have the receptors in sort of square bundles while humans have them on roughly hexagnonal grids. In this case, it's not clear which is better-- octopi are good at seeing vertical and horizontal lines, and can see polarization, but have trouble with diagonals; I don't believe ocopi see color at all, and probably aren't so good as vertebrates for acuity and edge detection. I have no idea how cephs are for motion detection, but given that they're visual hunters, I bet they're on par with most vertebrates.
Anyway, the basic argument is that studying cephalopod eyes is very useful because it allows us to compare a system that has evolved separately for a long time, so we have a much better chance to get around the blinders that come on when studying things that are similar to us, like rats and monkeys-- in many cases, monkeys' physiology is similar to ours, and rats', and cats', and even lizards' and frogs', not because the way they all work is the only (or even the best) way for animals to evolve to do something, but because some common ancestor, like an early fish, evolved one way that was good enough to get "locked in" to vertebrate evolution. Studying cephalopods gives us a way of looking at a creature that has a very sophisticated nervous system that has made "separate choices," so there is a good chance that anything in common ("convergent evolution") is a general principle rather than an arbitrary chance. Cephalopods are unique in that they offer a chance to study a complex nervous systems that is evolutionary separate.
This is potentially directly useful to medicine and such because being able to compare to such creatures allows scientists to validate or invalidate principles as general rather than arbitrary, and having comparison points that don't share so much genetic history in common can allow us to see more of the breadth of possibility for how complex nervous systems that allow intelligent, adaptive behavior can be set up. This, in turn, can help us with a general understanding of how our own brains evolved and work, which can lead to all sorts of medical and even theory-of-computation breakthroughs.
Also, as a less immediately applicable thing, looking at how different cephalopods are from us, we can begin to appreciate how different life that evolved on some other planet might be from us... most science fiction, and even real "exobiology" theory used in guessing what to look for in non-terrestrial life, is by necessity horribly biased toward the creatures we see around us. At least studying cephalopods, as the only creatures that have evolved "cat-level" intelligence that aren't vertebrates, can give us a hint of one other possible route to evolve toward human-level intelligence (although who knows how many other possible routes there may be).
Similar argumenst could be made for studying other cephalopod physiology and genetics, since they did branch off and evolve independently for so long, an since they were once the dominant large animals in the oceans, but that applies to some extent to the study of other phyla (or even kingdoms) as well. But cephalopods and vertebrates are unique in the level of nervous system sophistication, so on that alone they have a great potential to contribute to our understanding of general neuroscience principles.
(obligatory caveat, however: cephalopods do share the same evolutionary body plan controlled by homeobox genes, and so in fact still share a good deal of basic blueprint in common with us vertebrates-- it's important to realize that just because vertebrates, molluscs, and arthropods have evolved into neurologically sophisticated animals on earth, it's not clear that other body plans like anemones or sponges couldn't have developed into something as successful given a different "luck of the draw")
I could talk a lot more about cephalopod vs vertebrate evolution as an interesting comparison, but this post may already be too long to be accepted. I've read some interesting theories about why the teleost fishes won out over the ammonites in the most part, many of which don't depend on spinal cords and backbones, but rather on stuff like kidney function, or hemoglobin vs hemocyanin as the oxygen transport mechanism in blood, or the fact that the esophogus goes through the middle of the brain (but that's just an evolutionary pressure to take small bites, I think).