Never said that RAID replaces a backup. I suggested to backup the locally synced files. Cause that can be managed with an easy to use desktop application.
I do think that Hetzner will have some form of backup, cause they donāt want to lose all customer data if something bad happens (bad for reputationā¦). But their backup would be restored without control of the user. e.g. to the state of 12h ago or so (so no proper backup from user side of course).