What does backup & synced really mean..
Backup: Files are saved automatically. If you change files on your computers, their backed up files in the cloud change as well. It is important to have multiple versions of files so if you accidentally change or delete a file, we can easily restore an earlier version.
File Syncing: Is to ensure that two or more devices contain access to the same up-to-date files. Remember — lose it, and it is gone forever. If you add, change, or delete your file then all of the files synced in other locations will instantly change.
Storage Providers: Merely offer space for users to manually select files they want to take off their hard drives and save in a duplicate space.