What need does this address? Are cards taking up too much room in people's lives? This solution doesn't reduce the height or width of the encumbrance at all, and reduces the depth only by n*.76mm, where n is the number of cards that will be replaced. I don't get it. Also, http://c2.com/cgi/wiki?TheZenOfProgramming
For users, this must be some retro fad jumping the gun. Given the value of the transaction data going through this thing, it should be free at worst.