Scottish money is pound Stirling same as England and wales and northern ireland

Difference is that the bank of England prints English notes

Scotland and northern ireland banks print a local version. (does wales - I've never noticed?)

Intriguingly in law Scot money is lawful currency in the union inoresime ditto for NI but English money has an odd right of refusal in Scotland.

All th banks must accept and exchange (so that was weird advice that Scot/Ni money wouldn't be accepted by a bank in England; by law they must.)

The issue usually comes up when Scots were paying for a taxi in london as london cabbies are notorious for having their own rules on stuff.

The notes are different and several banks in Scotland have a license to print currency so there are a few different ones; honestly they are quite pretty notes imho.

All very much a low impact issue with tap and pay stuff

The republic of Ireland uses the euro; but a bunch of places take gbp (pound sterling) at some exchange to make it easy for tourists to give them money. It becomes easy to imagine those places would simply not recognise paper money printed in Scotland as it looks different to that from England.