The fizzbuzz test is not entirely about whether someone can do it. It's also about figuring out the style of the programmer. There's a surprising amount of flexibility to fizzbuzz; how is user input handled? Do they use a linter? How are variables managed/named? There's a lot going on, and it can be gamed just like anything else on both ends.

That said, the last time I had a fizzbuzz take-home test, it was infuriating -- my code is online.. what does fizzbuzz prove except to help make a company soc2 compliant?