Data synchronization is a way to ensure that you’re always up to date across all your devices, no matter what changes, and you typically get an online backup as an extra.
But when you’re using a cellular-connected Wi-Fi hotspot, such as the Personal Hotspot on an iPhone or iPad, you might want to press pause on iCloud and other sync operations. The sync services can’t tell whether you’re connected via a Wi-Fi network directly to the internet or you’re using a cellular relay.
Many third-party sync and backup service offer a way to pause. That’s sometimes a button or menu option that let’s you pause until you later choose to resume; other times, it’s a specified period of time after which sync or backup starts up automatically
