Or any previous device you might have had with Touch ID. Unless you change your fingerprints when you get a new phone. Or... You could wipe your old phone when

Or any previous device you might have had with Touch ID. Unless you change your fingerprints when you get a new phone. Or... You could wipe your old phone when you get a new one. Which can easily be subverted by simply disallowing the phone from connecting to the Internet. Perhaps, but you know what they say: If a (determined) attacker gains physical access to your device, all bets are off. But at least you would know if you lost your device. A password OTOH could be compromised without you knowing. Also, I am only saying that Touch ID is at least as secure as a username/password authentication scheme. If you want more security (perhaps because your adversary is someone who would go to the lengths of manifacturing a fake finger to fool a Touch ID sensor and also get a Faraday Bag to prevent you from wiping your device), the you should perhaps consider using 2-factor authentication.