If software engineers actually took the time to look at how intelligence is actually measured in fields outside their own, and how it relates to job performance, we'd have a lot less broken interviews.
When doing coding someone can have to solve an issue which doesn't have an answer on stackoverflow, so having problem solving skills is valuable.
Also, being good at algorithmics and data structures enable someone to come up with better solutions which might matter in a particular case.
I think algorithmic questions are better than asking questions about random methods from a particular framework.
Which is fine. If you're naturally talented at whiteboarding, great. If not, but you've prepared months ahead of time, great also.
If you're not naturally talented, and haven't prepared because of naivety or due to some principle, well, that's not exactly a great signal to an employer.