The aim is to replace "even the biggest of wallets."  An interesting concept with some rather significant shortcomings.  These being that there aren't enough credit cards supported by the functionality (healed by a cumbersome pre-paid card interface), the lack of retailer support for the NFC phone capability, the simple fact your credit card and cash doesn't have a battery life and your phone does, and that most people (probably) don't feel comfortable using a phone as a credit card.