I find the Desktop and Documents backup to be a poorly implemented feature, and would strongly encourage MS to disable it by default. It is confusing to most users, and in some ways may be dangerous. Or maybe I don't know how to use it.
When I first add an account to onedrive in the settings dialog of a PC, the backup feature seems to be enabled. As a result, onedrive will immediately relocate my local computer's Desktop and Documents folders (from the parent user directory to the onedrive folder); this in itself is highly confusing.
Onedrive will then proceed to transfer files to the cloud, and erase them from the local machine. This is rather offputting behavior, there may be files I don't want transferred to the cloud. Further, if I am on a laptop, and take the laptop to a locale without internet, I may lose access to the files.
I can disable the backup, but only after the files transfers have started. Further, the user interface is confusing; there are 'check marks' in the 3 folders (Desktop, Documents, etc) even if backup it not enabled, and the "start backup" button is active. The UI should clearly indicate whether or not backup is happening.
Onedrive allows multiple onedrive accounts on a computer: one personal account, and multiple business accounts. It is confusing how the Onedrive settings interact with multiple accounts on one computer, or the same account logged in to two computers.
The business and personal web sites are different (office.com for business, onedrive.live.com for personal) and this is confusing; if I try to log in to the wrong site I get a 'account not found' error, and no instruction to try the other site.
In my opinion, not well thought out and off-putting feature. Should be disabled by default.