I don't mind "how would you implement this basic server idea" or even "talk me through how you'd explore this algorithm puzzle", but I've definitely been docked for not having $OBSCURE_INSIGHT to $RANDOM_PUZZLE in 15 minutes, nevermind that I can usually get them sometime that evening when not standing at a whiteboard being interrupted when I pause narrating for 15 seconds to think, which is an appropriate timeline for any actual algorithms work. (I mean, I can count how many times in my career solving a math puzzle couldn't wait a single day: 0.)
Of course, I suspect some of those interviews are designed to fail you as part of H1B scams.
But it doesn't say anything about who's serious about getting that specific job, if every tech company does the same kind of whiteboard interviews.
To what extent are companies using whiteboards to test who is serious about getting the job? And who is willing to put in extra time and occasionally do unpleasant extra work?
Again not defending whiteboards, and I can think of ways to improve it especially for the more experienced engineers. But all else being equal in terms of two candidates experience and skills and fit; the candidate who was able to memorize things just for the sake of the job, who did research and who came prepared etc. Well that candidate might have the upper hand when making the hiring decision.
Right or wrong, companies do want to test for things besides current programming skills, like being a team player and do things that aren't easy or enjoyable. 80/20 rule maybe applies. How else to test this stuff if companies decide it's important?