These problems (known as fermi problems) have been out of vogue for over a decade now. Google is one of the companies that pioneered algorithm-centric leetcode problems as a replacement for fermi problems.
Leetcode problems are not hugely useful outside of the data given by solving a fizzbuzz. Rather, it’s just another excuse so interviewers can convince themself a person is smart, call it signal, and justify a hire.
The last time Google gave me a job offer, one of my interviews was literally a souped up fizzbuzz - straightforward imperative code with no trick, no complicated algorithms, and no fancy data structures. I suppose that may be the reason I got an offer, that I didn’t need fancy algorithms that I hadn’t prepared.
Ultimately it’s impossible to know if someone will be a good hire from an interview. Being a good engineer requires a bunch of traits that simply can’t be tested. The leetcode interview, as I see it, acknowledges this weakness and instead chooses to filter out low-effort candidates, as anyone persistent can practice leetcoding and interviewing (in theory).