As someone who (last week) ok'ed a guy with 35 years experience to skip the first round of interviews, only to then watch him struggle to write syntactically-correct code in a language he's (allegedly) been using for longer than I've been alive, I disagree. HR isn't a be-all-end-all metric, and it certainly has its faults, but it's very useful as a first-round filter.

I disagree. Kind of. There are many questions that are bullshit puzzle types but I do think HR and LC provides value of teaching when a Data Structure or algorithm is suitable for use. At the very least, It’s far better means of understanding the flexible use that college textbooks don’t teach while having test cases to see pitfalls of implementations. Having a community that shows ingenious ways of tackling problems is valuable too.