It's not either/or. We use them in case a developer forgets to run them, or hasn't set their environment up properly or similar.
The only reason you'd release a tool like this as a github integration and not an open source library (optionally with a CLI tool) is that you want to get money from it - nothing wrong with that, but that is very much an either/or question.
With the advantage that if the dev likes the advice, all they need to do is click "commit"