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 me, the remote-wipe ability is a killer app. Currently, when I lose a physical card, I have to go through a painful get-a-new-card procedure that involves going to my major websites and giving them my new card #. With remote wipe, when I lose my card I just remote-wipe it and order a new one. Also, this card will warn me when I'm too far from it so I won't be as likely to leave it behind.
I do something similar already, where I never carry around the debit card associated with my primary checking account.