To play devil’s advocate, a lot of that is now ameliorated by the decline of cash and the rise of certain neobanks. I’m in Denmark at the moment, and thanks to my banks (N26, Revolut), I can cheaply convert my savings (EUR) and spend in the local currency (DKK); either at transaction time (N26 and Revolut), or ahead of time (Revolut) all with minimal fees.
Yes and the Neobanks, both N26 and Revolute rely on fact that financial regulators across the block recognise each other, so N26 regulated in Germany can operate in Ireland. Etc.