Like some said its difficult to imagine japan having a scarcity of payment processing. They're known for being ranked high in terms of average internet speed and traditionally invested heavily in telecom infrastructure, the backbone upon which things like electronic payment are built.
Well the japanese people have been known to not be afraid to accept changes and innovation. It's not going to be surprising if ever they're the first country to run mainly on crypto. They understand blockchain and how crypto works with it so i don't think they'll ditch crypto and utilize only the technology.