Speed is always welcome, but I just wish prettier was a little less opinionated. Specifically around line length, it will just not leave my formatting alone. I find prettier formatted code much less readable than unformatted code, and this isn't a problem I have with other code formatters like rustfmt.
Prettier will affect your diff in ways you didn't intend to.
Remove a member from a destructuring assignment that brings it below the line length limit, and suddenly your diff is +1/-5 instead of 0/-1, making it slightly more difficult for your reviewer to see what the exact difference is between those 5 lines removed and 1 line added - it's not immediately clear which member was removed.
You try to rewrite a previous commit to fix a typo using Git's interactive rebase, and now the next commits won't replay on top if it because Prettier decided to reformat an entire code block.
Another fun thing to try with prettier: add a precommit hook that runs prettier, and then try to stage partial file changes.
No thanks.