I took their quiz without thinking once from a throwaway account because I was afraid of taking it from a real account and also because I had no context about what would be in it, which made it seem high risk. That made me realize it wasn't as scary a thing as I was afraid it might be, but also kind of summerizes what I don't love about it.
Later, I think I took the quiz from a real email. I think could have scheduled an in-person or something. But I was always afraid to: just like with the quiz, it felt like another layer of high risk, where being slightly off on one thing would kind of potentially blacklist you forever. (Which sort of sounds absurd to me now, but young me was like "what if it matters?" and "it'd be humiliating to not make it through.")
I work for a company that's been invested in by reputable venture firms so I don't think I'm bottom of the barrel as an engineer or anything. But the above anecdotes are to illustrate that I always found that the platform push my deeply ingrained risk aversion buttons. Which is interesting to think about.
With job interviews it's extremely annoying to prove you bona fides over and over, with every interview or application. But having the opportunity to do so only once seems even worse.
Edit: that said, I think doing a professional exam after college wouldn't have seemed risky in the same way as a ~12 question quiz and a couple interviews being so potentially determinitive.