They don't want you to know that the microchips in their cards can be reprogrammed so that you can wave it at reader and emulate somebody else's CC#, or that you can program any compliant RFID chip to communicate with those wavey card readers to the same effect, or that you can plant an RFID reader on an ATM or similar point and "skim" CC info without needing the user to explicitly swipe their card.
You thought credit-card skimming was bad when the skimmer had to be physically attached to the ATM? http://krebsonsecurity.com/2010/01/would-you-have-spotted-th... Now imagine trying to find something that concealable anywhere in a 5 or 10-foot radius of the ATM itself. Hiding the card inside a metal wallet won't help you there.
That's just a few off the top of my head...