> git reset --hard <commit>

Unless part of your surgery involves files that do not yet live in the history, or you're working on a detached HEAD in a mid-merge state, or... git reset --hard is a very dangerous operation unless you're 100% sure of the entire state of the repository. That is a very rapid way to lose work if you're not perfectly diligent.

And sure, you shouldn't have to back up .git or your workspace, but sometimes, it's a hell of a lot easier to ripcord out and say "screw it" if you have a complete workspace from before you decided to launch down the rebase hole or whatever.