Not everyone in my team wires up their pre-commit hook to run the pre-commit tool. I use JJ, so I don't even have a pre-commit hook to wire up. But the tool is useful.

The key thing (that several folk have pointed out) is that CI runs the canonical checks. Using something like pre-commit (the tool) makes it easier to at least vaguely standardise making sure that you can run the same checks that CI will run. Having it run from the pre-commit hook fits nicely into many workflows, my own pre-JJ workflow included.