I imagine the "super" cards will be in the range of $20+. That's probably fine for elite users and the security-conscious. It will be competing as a more secure alternative to smart phones. So it's in a niche market anyways.
For regular smart cards, maybe they could be paired with some type of online service that keeps an eye on merchants and perhaps validates transactions based on buying patterns. At the very least, it would be nice to receive some type of statement at the end of the month to be able to detect fraud. Otherwise, with nothing but the blockchain to go by, it would be basically impossible to know whether your grocer has a hacked POS terminal that is ripping you off.
So, just from what we've come up with so far, our universal POS terminal is looking at supporting:
- Smart phones via QR code / NFC
- Super cards via contact (/ contactless?)
- Smart cards via contact
- Online balance service
- Online transaction verification service
- Online "lite client" service?
Then on top of that add interfacing with the merchant's accounting system. And besides magstripe and contact/contactless credit cards, you're competing with Paypal and Dwolla and that new Canadian Mint thing. It's likely that none of those will cooperate to share hardware.
