You can get in some pretty serious messes, though. Any workflow that involves force-pushing or rebasing has the potential for data loss... Either in a literally destructive way, or in a "Seriously my keys must be somewhere but I have no idea where" kind of way.
When most people talk about rebase (for example) being reversible, what they're usually saying is "you can always reverse the operation in the reflog." Well yes, but the reflog is local, so if Alice messes something up with her rebase-force-push and realizes she destroyed some of Bob's changes, Alice can't recover Bob's changes from her machine-- She needs to collaborate with Bob to recover them.