This is very neat and a super cool idea. However, there's no chip? I try to avoid non-chip cards as much as I can for security reasons.

One more thing that crossed my mind is, what happens if you give this to the waiter, the waiter goes away to handle your payment and it happens to be outside of reach of your bluetooth ping; then you will most likely become worried that the waiter ran away with your card, or you will start ignoring it when it notifies you that it is outside of reach.

While talking about the waiter, what happens when the waiter accidentally clicks the "change card" button and takes the personal lunch on your business card? You might not notice until it's too late and people start asking questions..