This is very cool technology but I'm skeptical for its practical usage. Lots of people have already brought up the obvious pitfalls (atm use, accidental presses, banks potentially removing card liability) but I'd also probably carry around my important cards in my wallet just in case. So they aren't really solving the problem of carrying too many cards - at least for me.

It would be useful for things like gift cards and reward cards - but is it worth it for that?