SEPA also works easily because it's single currency for a single unified economic zone. If currency change was involved then you'd likely be back to routing through central banks or currency change banks and such.
- https://en.wikipedia.org/wiki/Single_Euro_Payments_Area
I don't know if I'd call that a "unified economic zone" without some qualifications.
https://www.europeanpaymentscouncil.eu/about-sepa/sepa-timel...