Watched that video, great stuff but the idea doesn't seem anything new compared to what Marcelo Garcia did for years, Marcelo did not use the body triangle but he has short legs, i remember a video of Marcelo saying that if you have long legs you should definitely use a body triangle if the opponent is standing and if he had long legs he would do it.
There are moves that for some reason we see all the time in pure grappling or in the gym, but never in high level mma, probably because jiu jitsu is more methodical, you pass, mount, take the back and choke, meanwhile MMA is more chaotic.
There is a saying in bjj that if you mount the guy you are better than him, because you had to beat all his defenses to reach that position, i guess that if you have the opponent's back and you have him already all knotted up you have already beaten him, but in mma if you manage to jump on his back early in the fight and the guy has a lot of energy it is just better holding position and not risk.
If you have the chance, watch the Michinori Tanaka vs Kyung Ho Kang fight, Kang had his back like 10 times, even with the body triangle, and Tanaka escaped every single time, some guys have a crazy bridge.
I guess if someone is THAT good he could make anything work, but the trend in high level mma these days is advanced basics and fighting safe, don't give anything to your opponent and don't be scared to win a "boring" decision.
If you notice, Demian Maia always goes for the armbar from the back when the round is ending, so he doesn't risk losing the round, should be a quite high percentage move and the transition has decent amount of control, but he always lose position.
