Googles interviews works according to their internal data.

Google bans any questions that you can find on the internet though, including all questions you find on leetcode (they have people who check this, including the member only questions), they want to ensure that candidates only do problems they haven't seen before. Some accidents still happens, but since they have 5 interviews per candidate it is very unlikely for anyone to pass without solving a few problems they haven't seen before.

So the process works when the candidate hasn't seen the exact problems before. For those who just gives leetcode questions verbatim it might be less effective, or even counter productive, I haven't seen any data on that.