My experience certainly tallies with what's been said here.
I did my DPV specialty course and on my second dive, was joined by a guy doing as DPV as part of his AOW.
The instructor had me do everything from taking the battery off charge, assembling the units (we had two different DPV models) and do the regular maintenance.
The guy doing the AOW watched and then did the dive in which he and the instructor shared one unit and I got the other.
Afterwards I got to strip them down, clean them out and put them on charge.
Then the specialty required a theory part, which basically came down to me telling the instructor what I'd learned about DPVs (most of which I'd absorbed while learning to take care of them).
Bottom line: the AOW gave that guy a chance to "play" with a DPV, while on the course I got much more hands on and walked away with a much better understanding of the topic (theory and practice).
I don't know how much this applies to other specialties, but I like the idea of exploring these ideas under structured supervision and coming out learning a lot more about the sport. Certainly builds confidence.
Having done AOW, it realy gave me an appreciation for how much I still had to learn and I see the specialties as a way of taking the next step down that path.
I'm heading to my dive shop this weekend to find out what course to try out next...
