In the case IMO in pressure sensors there is a primary need and that is to provide tank pressure top know if youare going to run out of air. any purpose beyond that is not a life necessary need.
Personally I know by now that on my regular average dive an Al80 lasts about an hour to 500-800 psi, that I can comfortably swim some 90 feet on a single breath, and that my wife's SAC is about the same as mine when I chase critters to frame shots etc. So under normal circumstances all I need is a watch for tank sensor and for emergency backup: turn off the camera and get closer to my perma-buddy... but I'm sure people sporting a Teric on every wrist and ankle believe I'M GONE DIE!!!
([invisible sarcasm tag] and they're probably not wrong [/invisible sarcasm tag])