Why Apple Pay Had To Be US Only At Launch
Which is probably why Apple was sensible to launch the product in the US, where penetration of NFC equipped readers is low and existing touch to pay services aren't popular. In effect the US becomes a beta tester for the rest of the world.
In Europe and Asia NFC terminals are common and touch to pay using Mastercard and Visa's contact free payment cards is widely used. Had Apple made it's service available in these markets those teething problems would now be amounting to a serious amount of trouble for Apple and the banks.
I've no doubt that Apple Pay will rapidly roll out across the world, something that Google has apparently been unable to do with it's similar Wallet service. What I'm not sure of is whether the service as it currently stands reduces any of the friction from the payment process. Currently for any Apple Pay payment it requires tapping the terminal with your phone, selecting the card you want to use and then authorising with a fingerprint.
Paywave and Paypass support PIN free transactions under a certain value - $80 usually. As those are likely to be the majority of your transactions using your contactless card makes sense. Apple probably needs to make the same authorisation-free transaction limit available on Apple Pay to improve the service to its users.