The security is a little more complicated than that. There are dozens of in-application checks and controls which try to guarantee that you're who you say you are, that you're authorized to make the payment, that you have funds and that the amount to pay is within certain limits. Naturally, a stolen card could be used once or twice. But never for very high amounts and never very many times: the card will request PIN and then the thief is stuffed.
And yeah, like Australia, contactless has been growing in Europe for the last few years. It's just starting in the US and these devices will help to trigger uptake (IMO).
