I've done a lot of dives, in the late 80's, early 90's. We didn't have any of this fancy stuff. For sure, you never rely on a single piece of equipment.

Except for more advanced (deeper) dives, a dive computer is fairly unnecessary. 700 lbs of air pressure left, go back up, slowly.

I did most of my diving right off the coast of san diego, where there are amazing kelp forests. I preferred less deep dives (35-50 feet) anyway... you start going deep, you have much less air/time down below.

I would assume this to be a very tiny market for users.