I'm going through this right now after I promised myself for a long time that I wouldn't debase myself with this sort of interview process. The rewards are too much, I sold myself out, whatever.

What I'm finding is that the leetcode isn't a memorization game, it reminds me more of my homework in grad school algorithms. Each of the problems is meant to tease out your practical understanding of an abstract concept.

It certainly doesn't guarantee you'll be a good dev if you can pass leetcode type questions, and you're not necessarily a bad dev if you can't, but I can definitely see where performing well at leetcode is a strong signal about SWE fundamentals.