Why? My experience with them was pretty bad. I took their assessment for web development, I think I even did an assignment, and got put on a video call with someone from Triplebyte. He never cracked a smile. Suddenly I got asked a bunch of CS questions that really were not very relevant to web development, some of which were entirely inappropriate like sorting a binary search tree. I even told the guy that I thought I was getting those questions wrong and he just scowled and said "well you just don't know when you're going to use this stuff." "My point exactly," I thought.
Ultimately I got rejected.
The whole idea that you can boil down a candidate to some coding challenges and a video quiz is bad. I do like the idea of streamlining the hiring process for developers, but there's more to it than knowing a bunch of stuff, because that can be gamed. And quizzing me on irrelevant material was a bad move. A firm like Triplebyte won't be as good at interviewing a candidate as the employer itself, and may even keep perfectly qualified candidates out of view from all employers affiliated with them.