I think they shouldn't back up git objects individually because git handles the versioning information. Just compress the .git folder itself and back it up as a single unit.
This is a good point, but you might expect them to back up untracked and modified files in the backup, along with everything else on your filesystem.
Better yet, include dedpulication, incremental versioning, verification, and encryption. Wait, that's borg / restic.
This is a joke, but honestly anyone here shouldn't be directly backing up their filesystems and should instead be using the right tool for the job. You'll make the world a more efficient place, have more robust and quicker to recover backups, and save some money along the way.