From the second video it looks like the device supports a key fob accessory which contains a second camera/LED system. This seems to communicate remotely with the phone, which could be placed in the user's pocket.
He mentioned that there's a number of accessories available, which leads me to believe that there's a lot of various devices that the external camera can fit into. Perhaps even some way of alerting you to card movements through vibration or something.
That's exactly what the haptic feedback accessories mentioned are.