As a Yank, I get bills, can mail a check or usually have my financial services do it for me. It scales, and North Carolina does not have a local system used for 90% of local bills that is entirely different to Nevada. One system, checks/cheques with wire transfers as a backup, and proprietary systems built on top.

As a European, I get bills from the UK and another country, in each case they prefer to be paid using whatever local payment system they have. Example: an EU non-UK government bill on top of my pile, they want a Bankgiro, no IBAN anywhere on the form. Maybe with enough digging I can get an IBAN. Clearly the government thinks IBAN-payers are weirdos or they would have specified it. Another half hour of my life will soon be wasted making an inter-country EU payment.

TL;DR: UK-to-UK vs Nevada-to-Nevada payments, UK wins, Nevada catching up. UK-to-Sweden vs Nevada-to-North Carolina, no comparison, US way ahead in practice, Nevada-to-North-Carolina is indistinguishable from Nevada-to-Nevada.