> Using cloud services, in addition to local backups

That's exactly what he had - it didn't safeguard against file loss, but caused it.

But local solutions can also cause file loss, if you don’t know how to use them correctly.

For example, rsync and rclone will happily overwrite/delete your files if you mess up the argument order.

The problem with OneDrive is not that it is cloud-based, but rather that its design is somewhere between baffling and intentionally user-hostile

Yeah, exactly. The vast majority of the time having a backup saves you. Microsoft just managed to make a product so bad it harms users. It's like if you installed a smoke alarm, only for it to short circuit and start a fire. In these cases, the "protection" is the cause of the harm. Bafflingly bad.

Only because he didn’t understand how “syncing” works, and deleted the files in the cloud which deleted them off his computer. The “file loss” was pure user error.

If a feature requires training in order to use it without risk of serious data loss, perhaps that feature should not be enabled by default.