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.
With the money they raised, after spending so much on marketing, I assume they downsized, lost some talent, and pivoted mostly to a sales-driven recruiting business for their top clients.
I can't imagine the difficulty to accurately measure the success or failure of long-tail HR hiring processes like phone screens. The success or failure of a candidate post-hire has so many variables it must be very hard to attribute them to signals present in a screen. I imagine most of the data points are derived from signals found in successful candidates, and then trying to find them in an assessment or screen.
Its really hard, and I hope the negative tone of my comment does not suggest I don't respect the problemset and the people willing to throw themselves at it.