Switching iCloud selectively on and off can lead to catastrophic failures. I would very strongly advice against it!!!
Example: You want to try a backup, so you disable iCloud and restore that backup. Now you decide you don't like that and want to go back to iCloud so you delete all your songs and rejoin iCloud. Result: Everything in iCloud is deleted because everything you do after you have joined iCloud is tracked and replayed once you are back in iCloud. That's how iCloud works and I have no means to change that.
So if you really want to test things while not affecting iCloud the only way to do that is to reinstall the app.
Bottom line: If you leave iCloud, make it a habit to reinstall the app before joining iCloud again.