Here is a question:" When requesting some-one to send you money via a mobile payment schema, would you want them to send it to your card-number or your cell-phone number?" What is the most suitable routing number for a mobile payment?
If we were to pose this question to consumers, I am sure that the majority would pick a cell-phone number. Using a cellphone number as a target number for mobile payments will also be more secure as it would not compromise a card number (which, if it falls in the wrong hands, can be used for fraudulent transactions).
This means that, if we were to deploy a P2P solution based on credit (or debit) cards, a mapping between the cellphone number and a card number will have to be maintained. An interesting question for me is who should ideally be in charge of this mapping table: a bank, the mobile operator or the card association?