I think it's just because people have only now "discovered" it ... slowly it will become staple like a lot of other things.
Most fighters are conservative, they only want to try out the few techniques that others have "proven" to be safe and cage worthy. There's a reason for this, because back in the early days a lot of guys would get absolutely smashed trying out flying kicks, drop kicks, off balance flips or trips etc that got them countered or taken down. It's one thing to try these things in sparring where the counter won't knock your lights out, another entirely in a fight.
Usually the ones that push the barrier are the super-elites and champs who are so far above everyone they face in terms of reaction time, TDD, defense etc. (like Anderson, GSP, Jones, Machida) that they can afford to try out new stuff without getting clobbered down the ladder for a few seconds worth of experimenting.
Just a few years ago you hardly saw anyone use the teep / front kick, or if they did it was more of a push kick to the body instead of a power kick to the head. Anderson KOs Belfort with it, then Browne KOs Overeem with it, and suddenly the floodgates have opened. Now you can hardly go 3 fights without someone attempting one. Same with the high kick 7-8 years ago ... at the time only CroCop and a couple of others ever threw it, the rest only used low kicks for fear of being caught off balance. Then Gonzaga crocopped crocop, and people realized you don't have to be an elite K1 kickboxer to throw it well.