This is a brilliant idea! You can also make stickers out of the qr codes to stick on items in a store and scan at check-out just like the UPC code too. There are many ways to implement this. I really like what you are doing!

Just one question though. How are you able to exchange the BTC for USD so quickly and deposit it to the card holder's bank account? This is something I need to know before deciding to buy one.

Keep up the great work!