Is it possible to backup my iCloud contents?
I discovered recently that TimeMachine backs up all iCloud data. As long as you use TimeMachine, it is safe to use iCloud. If you want to recover your old (accidentally) deleted files, simply open Pages.app for example in the iCloud view. Then, you can just browse through your file history.

E.g., if you deleted the file today, just go back to yesterday and recover the file in TimeMachine