The value of mobile payments is that it helps attract new customers... and relatively cheaply. If the bank can attract a new customer and retain them until they are profitable... now you have a busines case.
How does a customer become profitable....? By engaging in the other services available from the bank. "I'll have some fries with that deposit account - float? - What's float? I will take some insurance, a car loan and a mortgage please... and oh yes, please charge me a monthly fee for the services with my deposit account."
Mobile payments will skyrocket... when banks internalize this fundamental truth.
... and I'm done with this guy!