Why would shops or users want this?
When I pay with PayPal, merchants get slapped with more fees than if I had paid with a credit card which in some cases is already too much. This is doubtless because PayPal takes a hit when money is deducted from a credit card and then it has its own markup on top. NFC is likely to be exactly the same - NFC processor tops up from credit card so fees it charges by definition must be >= credit card fees.
How is NFC going to take off when the proposition is for stores to give even more of their money away to payment processors than they already do?
And for consumers, where is the convenience of whipping out an expensive phone versus a plastic card? Do people really want their phone to not only be an attractive item to thieves in its own right but also for any money it contains?
I think NFC would be more useful and palatable if it were just an RFID stuck into a credit card. If people absolutely want to see their transactions on their phones I'm sure there is an app for that. No need to insert yet another middleman into the chain.