There's a lot of ways around the broken/lost/phone-less populations in a system like this. The phone doesn't really do any more than provide the initial authent

There's a lot of ways around the broken/lost/phone-less populations in a system like this. The phone doesn't really do any more than provide the initial authentication and receipt delivery. If these really took off and started replacing normal systems it'd be really easy to add a receipt printer and to add a card reader for a 'members card' that does the same thing as the QR code on the phone.