Security Shortcomings of the Contactless Smart Cards

Smart cards with contactless interface(using Rfid protocol) is growing. This technology has now been used in credit cards, passports, epasses, etc.

However what are the security shortcomings of the contactless (using rfid protocol) smart cards, especially if the decryption of the data happens on the card reader.

I came across set of videos done by e-tech. This show how important is to have adequate security in contactless smart cards. Most of the smart cars that these guys show uses the rfid protocol.