One good use of DPV other than just playing and cave diving. There was a dive shop at the conference hotel I was at in Hawaii that ran shore trips and one of the sites was a bit far down the coast for an underwater swim. So they would DPV down to the site, then dive it without DPV and then DPV back. I would have done that one but they were not running it on the days I was diving with them. Was a good conference. I would meet DM for a shore dive around 8 am or a tad before. Do an hour long dive. Then quick shower and to to work.