ApplePay is only limited to the US, while there are lots of people in the rest of the world. So no, it's not a threat at all in the grand scheme of things.
Hehe don't forget one more thing, Apple's solution only works for US resident customers shopping at US merchants. A lots of people won't be able to use it when they visit the US they don't have a residence there. Still leaves the vast majority of the world untapped. At least PayPal works in more than one country.
I don't think apple pay only works with US phones with US merchants.
Apple pay is a major selling point for the iPhone 6 (apple sells iPhones around the world) so I don't see why they would only make this feature available in the US.