Local backup is very useful and an essential role on securing data against unwanted happenings, but with the dawn of broadband and not that so expensive online storage, and some more offer a free online storage, you don’t have any reason’s not to back up your important files online as will.
On-site data backup is better than no backup at all, but if your on-site backups go up in flames or otherwise end up inoperable, then you're out of luck—unless of course you've got a backup online, that is.-LifeHacker