To give you a more serious answer, the teep hasn't really caught on in MMA yet for the most part.
It's a deceptively hard strike to do and requires a lot of balance because you're having to push your opponent backwards while keeping yourself standing and strong. I've heard people claim that it doesn't work because you're giving the leg to a wrestler, but seeing as its so rare you even
see a teep in MMA its hard to say whether that's actually true. There's a lot of shit we didn't think would work in MMA until Cro Cop came along.
What you're seeing in MMA are usually sloppy mae-geri front kicks from karate.
Because the foot bounces off the target pretty much it becomes a good non-committal weapon if you're good at it. Conor McGregor's win over Chad Mendes is largely because of his commitment to body kicks, while he was being out wrestled everytime he snapped a body kick at Mendes he wore at his gas tank.