This is an extremely bad idea, since while you can cancel a credit card, you can't cancel your fingerprints . It's just a matter of time before someone figures out a way to use a fingerprint gathered by some undetermined means (discarded coke can, mail-in response form, etc...), scans it and spoofs the terminal into draining your account. And since it's allegedly been "signed" by your print, you can't refute it.

Quite frankly, this system scares the heck out of me.