They're not. It's a list of apps that use iCloud for synchronisation.Then why are all the rest of those switches for backup?
If you turn them off, then those apps (e.g. Reminders) don't sync across to your other devices but just stay on your phone. And are still backed up when you do an iCloud backup. In fact, turning an app on actually removes it from your iCloud backup as it's not necessary; it'll simply sync back from it's dedicated iCloud storage.