One wallet, more than one screen
Add a card on your phone and it shows up on your tablet and watch. Sync is encrypted on the device first, then uploaded as ciphertext. Replacing a phone does not mean scanning the wallet again, as long as you can still unlock the account.
Cloud and Family both include it
Multi-device sync is part of Premium Cloud and Premium Family. Cloud is for your own devices. Family adds shared pockets for the household on top of that same sync. Premium Offline is a one-time purchase with no account and no cloud sync.
Edits wait for a connection
You can change cards without signal. Those edits stay on the device and sync when the connection comes back. The offline checkout page covers using barcodes at the register while that queue is waiting.
