Saves you tearing your hair out
On a bus journey I was writing a post when I managed to click on an entire folder while navigating the Grav CMS menu. In the moment of confusion that followed I thought it was a new post. Obviously I didn't want to create one, so I hit the Delete button and confirmed. At that point it dawned on me that I'd just deleted everything!
If I hadn't had a backup — or rather, if all my changes hadn't been synced to the repository — there would have been nothing publishable. I stayed calm: I've got it all. First I checked the backups, which run regularly every week. Unfortunately I'd made quite a few changes since then, so: git. If I hadn't changed anything I could just restore from the latest backup and be done.
I use the Git Sync 2.0 plugin — it can sync content on save and on changes (including deletions). It works both ways, so if you need to edit multiple posts at once it's the ideal route. Rolling back to a previous version is simple: discard the last change, wait for the sync to finish, and done!