The poll suggests this for black belt divisions at IBJJF events. However, I think it would be a great idea for finals of any division except maybe the most novice ones (kids, white belt, etc).
An alternative is to make it an opt-in option. So, if both competitors agree, then it’s submission only, otherwise if either disagrees, then just do a regular points match. Although obviously this alternative has some unfairness issues.
I won far too many matches by 2 points or even on advantages. When the time runs out and I’m only up by 2 points, I feel like I was saved by the bell, like I never was put to the test. I do see jiu jitsu as a chess match, and respect the game for its technical merit, but in the end it (especially a finals match) is a battle. To win a battle you have to make the opponent give up, no excuses, no referee close calls, etc.
All that said, I don’t think I would want every match to be submission only, lol. Or would I? I’m doing the US Grappling submission-only tournament in September. If it’s anything like what people say it is, it’ll be a great experience. Here’s a highlight from one of their submission-only events: