Earlier quoted context omitted.
These questions should definitely be part of the interview process, but not all of it. I've done a lot of these kinds of interviews and I've definitely seen candidates that speak impressively but fail basic technical tests. If you don't actually verify the technical problem-solving ability of the candidate in some way you're forgoing signal that can massively increase the confidence you can have in your decision.
Anecdotal but we've hired an engineer who was pretty decent in the interview but couldn't figure out how an if statement worked in a legacy codebase. Yes, I wrote that right. He struggled to understand conditionals in general when building his own logic. The guy even had a masters degree.
I then did a course on assembly programming and having to be extremely structured and using jump statements actually helped me a lot in easier to use programming languages.
Point of this comment is that people might be good at a lot of things, while just having some weird brainfuse related to a very specific thing. That said, not using if statements makes programming rather difficult.