When it comes to working on deep-sea cephs/stuff, SCUBA proves useful purely for visual imagery - you know, pics of expedition hero jumping in water when net or sub is coming up, or fearlessly jumping in water in the middle of the night, middle of the ocean, bright lights (to get imagery of the juvenile cephs in the upper 10-or-so metres), but in general, for an 'expedition' (usually involves BIG $$ and BIG equipment), SCUBA isn't that helpful.
An 'expedition' is a funny term to use. A trip out in a boat for coastal dives could be called an 'expedition', if you have an aim, particularly if you are looking for something, though I think 'expedition' in the context you (and most people) use it is when you start chartering stuff, spending colossal dollars, have many personnel doing their bit, are gone for several weeks, and the whole thing is caught on film.
Me, my preference is for the small 'expedition', 1-4 people, day- or overnight trips, set and achievable objectives, multiple dives for therapy, a little fishing, and NO CAMERAS, although I've done a few of the larger/longer ones.