> A real backup solution ought to cover the case where you deleted the wrong file, and you find out the next day. Or it got corrupted somehow (PCs and disks can explode slowly) and you find out the next time you open it, a week later. If the cloud service happily replicated that change, it can't be used to restore anything.

a) my cloud storage has file versioning b) as I mentioned, I have a ~24hr old snapshot as well as a ~30d old snapshot

The worst practical case is that I lose a month's data, and I'm fine with that.

Sure, there are different acceptable levels of restoration and backup but a 'backup' by definition is just a spare copy of data made in case the original is lost or damaged. I was only pointing out that a cloud copy is a backup, albeit a fairly weak one and as you say not useful by itself in every eventuality. It's just absolutist to deride cloud storage as "not a backup" as it can absolutely save data that would otherwise be lost.