I don't see any point in developing new hardware. Bitcoin is the most adaptable currency invented (I consider it the ninja currency) and should use whatever is already ubiquitous. Magstrip readers are plethera, barcode scanners too. I don't see many smart card scanners in America, though it's probably because I live in a rural area. I'm sure there are a lot of magstrip haters here, so I probably shouldn't have mentioned it. I'm sure many other countries are technologically way ahead on the smartcard trend to buy their bullet train tickets. I hate to be a pessimist, but I see the way most average Joes behave and they won't be using iPhones, smart cards, or any other new gadget any time soon in the retail environment. They will be using magstrips and paper. If Bitcoin cannot adapt to magstrips, paper, and sms, then it will require bucking the system. It's too expensive to try to educate the masses about new gadgets.

tl;dr  Bitcoin is the most adaptable currency and should use what is already ubiquitous, because it's too expensive to educate a market.