Don't know what to say, but I think this is one way to iron out senior folks who don't do daily coding and most of the time was on designing, diagnosis or debugging.
When you go to interview,you may be interviewed by a fresh graduate who throw you a trick leetcode question that is, pretty much, requiring you come up with code in 30 minutes. Without a few months careful practice, it's hard to get it right under stress.
Coding challenges are like driving, you drive at normal speed in real life so you can drive everyday safely, but for interview, your brain has to be speed up the max speed under pressure, not everyone, not even the brightest guy who can do this well, again without months preparation.
I got interviews at Amazon etc but I never had time to practice leetcode etc, there is no way I can pass its whiteboard process without at least 3 months preparation I feel, and I absolutely have no time for that.
How about hiring senior folks as a contractor for 1 or 2 months then to decide the level and pay and such? nobody wastes anytime and no obligation either.