This is cool, but has anyone ever needed to rewrite commit authors or dates?

Yes, for instance it could be useful if someone’s been accidentally committing with a bogus email address. Or if you’re cleaning up some sort of mess and would like to recreate an accurate history.

Obviously as with any “force push” situation, the usual caveats apply if this is on a branch others have checked out, but if the mess is big enough, it is sometimes worth it to send everyone a script to reset or just to have people delete and re-check-out.

yes; when i wanted to make it look like i didn’t procrastinate for a week and implement the entire feature in one day

Yes. Absolutely! Many times I had a wrong configured terminal and messed up the author. Often I work in different projects, privately and in my work, and I use different authors for both