This article was recently published in the NY Times which may be of interest.
The link is http://nyti.ms/1tvewA8
I dont understand the technology however the article appears to link the adoption of smart phone payments to
- the use of NFC technology in I phones
- development of some standardization of hardware / software technology between different applications
- the adoption of credit cards with micro chips ( as is occurring in Australia)
The applications quoted make the achievements of MNW seem pretty impressive.