Well, first off, that 85% is really a stretch. Most of that number (well, I think most of it is made up, since only Apple reports sold numbers, and the rest report shipped, and the media is making up a lot of "others", but I don't want to start THAT argument) is for phones that are not top tier phones with NFC in them.
The bank still has the transaction, so there shouldn't be an issue with a refund.
It doesn't have to just benefit the business, but the banks and CC processors as well. So why haven't they embraced it before now? Seems like it would have been a no-brainer, but according to your earlier post, none of the major banks, and only MC supports Google Wallet? Why is that? I think the main reason is a lack of security, but who knows. Maybe Google just hasn't taken the time to work with them.