Your setup follows you — through your own iCloud, not ours.
Start a movie on your iPhone on the train and finish it on your Apple TV at home, exactly where you left off. Klave syncs your setup across devices — privately, with no account to create.
Sync runs entirely through your personal, private iCloud — the same one your photos and notes use. There is no Klave account and no Klave server that sees your data. Sign in to iCloud on each Apple device with the same Apple ID and Klave keeps them in step automatically.
Because resume points bind to the title rather than a specific copy, you can start on one device and one source and continue on another device and a different source without losing your place. Your setup survives — synced to your own iCloud.