Can't believe this is proving to be so hard...
...doesn't anybody watch Japanese movies? Cash is still widely used, and credit cards are unpopular. Electronic wireless cards (and some mobile phones), however, are popular to the tune of an estimated 100 million in deployment [*] (and yes, I'm aware the population is only 127 million!) and able to be used for trains, vending machines (yes!), hotel rooms, general purchases...
Personally, I think these cards should need to be 'charged', it can be as simple as logging into your bank website and allocating funds. That way it is useful, but if it is compromised then you only stand to risk what you're charged it with.
As for identity. FAIL. It is hard enough to prove any means of secure form of idenity in a paper-based format. I am me, my passport says so. Is it a real passport? Can it be trusted? Did I manage to fool the authorities and rip of some dead guy's identity? I know my passport is genuine, but what if some immigration official in Dumbnuts, Minnesota challenges me to prove it's a real passport. How do I do this? Call my embassy? Then what? [re. Hamas Dubai assassination for the problems of paper document authenticity]
Now apply this to an electronic format. Data is invisible and has a propensity of being rather transient. You can inspect a real passport. If necessary under legal jurisdiction it may even be possible to take it apart. An RFID tag? Because it talks to a computer and the computer says so? Is that it? Try http://www.theregister.co.uk/2008/09/30/epassport_hack_description/ and http://www.theregister.co.uk/2008/08/06/epassport_alteration_demo/
.
In short: Payment method, could work. I might find it convenient if they were to roll out something like that here - finding change for car parking and coffee machines is always a bother. But for proving my identity? Get real...
* - source: http://www.contactlessnews.com/2010/07/20/report-card-use-m-payment-increasing-in-japan