Geektastic: Can anyone explain why it is better than just using the card itself?
You probably already have your phone in your hand, or more immediately available than your wallet, and it's fewer individual movements (no need to take card out of wallet etc). Also it's very quick, feels like the future, and means you get going quicker. I especially like it when paying for petrol because there's no product to scan, just walk into store, say how much you want, wave phone at terminal then walk out again.
The obvious downside is if you don't know if the terminal will support paywave you end up with your phone and your wallet in your hands so there's more to juggle.