Sharing a personal anecdote - when Apple Pay first launched, it only worked in the US. A more accurate statement though was it could only be set up in the US. I very shortly after moved to Australia, where tap-to-pay is the standard.
It was kind of crazy because despite not officially being supported, Apple Pay worked everywhere in Australia. Whereas only a small handful of merchants supported it in the US, 99% of point of sales in Australia supported it because it was based off the standard.