LogTen Accounts allow you to use your LogTen subscription on multiple devices. The LogTen Account is separate from, and does not need to be the same email address as your Apple ID/iCloud account. You can have one email as your Apple ID and a different email for your LogTen account.
Your logbook data will be connected through LogTen servers to your LogTen account. This means your irreplaceable flying life will be backed up automatically.