From a user's perspective, the current user experience around credit cards is pretty good. You get a tangible, color coded interface and a tactile interaction mechanism. Swipes work pretty reliably and the time it takes to pull out a credit card is very small.
When you're competing with a solution like this, even minor differences in UX can be dealbreakers. One thing I didn't see much talk about with the iPhone 6 launch was that Apple were the first phone makers (AFAICT) who managed to put NFC on the edge of a device rather than the center. I've tried paying with Google Wallet before and mashing a giant phone against a tiny contactless reader was error prone, frustrating and made you feel like a dork doing it. I tried it 2 or 3 times and then went back to credit cards.
I can't imagine how much worse this CurrentC solution is going to be in real life and how hard it will fail.