Backups are funny things. I tell the backup to use certain hardware and it gets ignored and uses hard drives I don't want it to use. I think I'm getting a full backup only to have Windows updates reboot in the middle of the backup and kills it off. I do a test run that says it fails, but then find out there's no errors.
I attempt a restore and the catalogs say the data isn't there despite the fact that I can see the backup files.
It reminds me of when I was at Price Waterhouse in the late 90's.
In San Francisco, where the main hub was, they had a power issue and the servers all shut down due to an air conditioning outage. I was managing the Portland IT at the time. Even though they said they had good backups everyday, the backup tapes were blank. People down there were fired when the partners couldn't get their data back.
Backups provide a false sense of security and they are difficult to trust. I prefer to have servers that sync to others rather than backups because you can test to make sure the data is actually there. Not many companies have the money for this though, so we go on trusting our backups will be good.
Online backups are a joke for so many reasons. If you have to ask why then you don't understand why they don't work in a disaster. If I have had a good night's sleep for once I may have the patience to one day explain it.