Before SEO communities argued what were part of the model, thinking some things like clicks didn't matter. Truth is Google did everything you can imagine, including clicks, now they all know it instead of having to guess.

Still wont change much though, its very hard to game since Google has a lot of ways of mitigating click farms or it would have discovered a long time ago.

Back in the day a friend mentioned you could choose what version of a phrase you wanted to make the canonical for a search autocompletion by embedding a broken image call to a SERP page for the version of a keyword you wanted to be more popular.

Google has tons of ways to identify real users versus fake users. And lots of the fake it until you make it efforts leave statistical outliers that can lead to ignoring or smoothing away much of the benefits, especially if there is no fire following the smoke trail.