I don't know if self-checkout and clerks with ipads will replace traditional retail in the near future but who knows. In order for an Ipad to replace a terminal it would need to be redesigned to act as an NFC receiver, support PIN debit and include a crypto element for EMV. It would also have to be designed to be non-serviceable in order to be compliant with key EMV rules. Those things could happen but I don't know how much incremental hardware revenue it would generate for Apple