wow, identity theft just got stupidly easy.
As for the retailers not accepting the card, that seems unlikely. why would they care? They aren't in the business to aggravate paying customers when the tech is already in place. which would you rather do? sell a cart of groceries to a yuppie with a bluetooth credit card? or pay your employee 12.00 per hour to put back 150.00 worth of groceries or worse, eat a 75.00 lunch for refusing tender? I don't get it.
I do get why people would be opposed to this type of tech, both credit card companies who will lose their main forms of advertizing and dispute resolution, and consumers who would worry that being able to duplicate any credit card instantly could be abused... that said, legally I think this is in a legal grey area, not unlike aereo. The technology itself just isn't illegal, which means that while credit card companies could potentially cancel your card for a breach of the TOS, the company itself is probably safe from any legal attempt to block them.
Personally, I think the tech is cool. I like it. I think using it might actually be safer than using a regular card, if implemented properly(especially given the ease of duping a card in the world of "coin". I also think that this fills a huge gap in NFC tech: adoption. I can substitute 7 cards for one that I swipe exactly the same way. I can't substitute my phone that is only applicable in 10% of cases, I can't substitute 7 cards for 7 e-wallets that are unique to the 7 places in town that actually accept any form of NFC and I can't substitute a 3 second ritual of choosing a card and swiping it with a 15 second one involved in opening an app before every use. NFC was killed by retailers who didn't want to let the viable players step in and just do it. As a result, NFC is pretty much dead at this point.