Wanted to try this thing out, so I opened an Amex Serve card and placed 50 bucks on it. Searched for vendors nearby that accepts it and mostly saw vending machines. Went to lunch at Panera Bread and saw it had NFC payments available. Tried it just for the heck of it and went through flawlessly. This is with the wireless charging back cover with $60 emergency cash folded against the battery. I suppose we can use anywhere despite the limited outlets that Isis states that we can use it? The only con is the length of time it takes to xfer money from my checking acct to the Amex....5 business days! Cash can be loaded onto the physical card for instant credit and it shows up in the app, I think.