I don't think being one word longer ("uvx ruff format" vs "uv format") counts as being is worse.
I think it is much worse to create a special case that obscures the actual formatter being run and how it is being run (is ruff now preinstalled, or is it downloaded and cached in the same way as other tools?)
Not really. If you know about uv, you know how to use "uv tool run", so you know how to use any formatter of your choice (which you can find easily on Google, arguably easier than reading the documentation and learning about uv format).
Well, it is arguably worse to run an unknown, not version pinned, unconfigured formatter over your code and expect it to improve things, unless the code is an utter catastrophe in terms of formatting.
_You_ may find it irrelevant, but speak for yourself. I don't want dependencies, that are not version-pinned and checksummed running over my code. It is certainly not irrelevant to me.
I think it is much worse to create a special case that obscures the actual formatter being run and how it is being run (is ruff now preinstalled, or is it downloaded and cached in the same way as other tools?)