I'm on record as being deeply skeptical about the handset-as-wallet proposition, or the broad use of NFC-enabled phones as a way to pay for goods or services.
So it's good to see O2 (one of the NFC cheerleaders in the UK) embracing reality and (at least as a first step) realise that trying to replace credit cards is a losing proposition. Instead, it's adding to their numbers with its own-branded plastic, together with NatWest bank.
It's doing some clever stuff with balance notification via SMS, and it's also a good call to spot the branding linkage around prepay. I'm sure that in time, O2 will probably have another bash at the "mobile wallet" as this article suggests. But for now, it's pleasing to see some reality about mobile payments - a mobile operator *enhancing* existing payment mechanisms, rather than trying to substitute new and clunky alternatives for current perfectly-good ones.