Which is complete bullshit with the Euro having been specifically invented to be used across the EU.

I had a similar moment of stupidifiedment trying to park in Germany with a phone set to Dutch region. Euro in cash works everywhere Euros are accepted but apps on the freaking Internet? Nah, gotta restrict that to the publisher country only.

Switzerland is not part of the EU nor the Eurozone though. It's still a shortsighted stance of Postbank not to open the app to at least the DACH region, but that specific argument carries little weight.