Sorry, I don't see any way this can work reliably.
No one is stopping you from demanding the payment method of your choice, even if that's Federal Reserve Notes.
NFC enabled smartphones will work a lot better for casual transactions because they can trigger real BitCoin transfers that can be quickly verified by a trusted node.
That will work a lot better for people who a) have smartphones b) know how to use them c) want to use them. It won't work better for the drunk at the bar (he pawned his smartphone long ago), the guy who can't afford one, or Grandpa who can barely grasp the cellphone concepts of "talk" and "end".
Sure, for you, you might say you want to be paid in bitcoin through your smartphone.
Bitcoin, to be acceptable as a mainstream currency, ought to be convertible to all kinds of forms. Many people indeed will appreciate a paper "banknote" backed by bitcoin. That banknote has to be backed by a company, which will bother libertarians, but not the casual beer drinker. On the other hand, the banknote exchange could be shut down like eGold or Liberty Dollar, and it wouldn't have the protection of the Secret Service going after counterfeiters and could be brought to its knees by people who redeemed the BTC with counterfeit notes, so choose your risks.
We all wonder when Bitcoin will be useful for something more than "bitcoinxxx" porn and some offshore VPN hosting and Tuesday and Thursday babysitting in south Wichita Kansas. The more media the better - the tangible one is important and ought not be brushed off.
Besides, at some point, such smart cards may as well be RFID (they're going that way already), and in a world of RFID cash, would certainly be readable by your smartphone. You just whip out your smartphone, touch the bitcash card to it, and it verifies that it's good. Best of both worlds.