Turning syncing off warns that data will be lost (huh? I don't want you to delete anything, just stop syncing the two data sets).
Tis all a muddle.
And then backup. You have to choose between backing up to this computer and backing up to iCloud? Why? I certainly don't trust iCloud with my only backup, but having it as a remote adjunct would be handy. Why can't I back up to both?
It's horrible.