> many companies just blindly do it.

Yes. A while ago a company contacted me to interview, and after the first "casual" round they told me their standard process was going full leetcode on the second round and I'm advised to prepare for those if I'm interested in going further.

While that's the only company that was so upfront about it, most accept that leetcodes are dumb (need to be prepped even for a working engineer) and still base the core of their technical interview on them.