I think you mean this as a minor criticism, but this seems to be exactly the point of the service. To figure out a way to find people that are actually competent at the work itself, but not in the somewhat uncorrelated skill of public speaking & live coding w/ an audience.

Also a good way of identifying people that haven't gone to top tier elite schools but are just as good or better as those graduates: Recruiters at a FAANG might disregard a graduate from Generic State University w/ 2-3 years of experience under normal conditions, but if you get one that is willing to place a $1024 bet on themselves and then passes the tech interview with flying colors, it's a much easier sell.

Now, with all that said, after 6 years I'd still really like to know what their long-term outcomes are. What's their typical tenure at that job, where do they land for $job +1, +2, etc.?