content: What do you mean traceable, I have issue with this method because can be faked using a camera and a printer. It is just a code unique to you that means it would work from paper as well as the phone, or you could just pull up a photo of someone else's code on your phone. At least our requires a chip of some sort adding a bit more complexity if not security to duplicating. Then again if it is coming from my bank why not just us a card from my bank instead of adding google/apple to my banking system. Edit: also my plastic card from the bank has never had a dead battery interfere with my ability to pay.