Which would help tourism if tourists could buy it, but the app asked for some Id and double-checking the web asks for an European address (UK is also listed)
I don't want to become an expert on buying the optimal set of tickets from multiple regions.
Having the ticket would help a lot navigating around without fear of having the wrong ticket or making dealing with delays or cancellation even more frustrating.
For buying it, ID might be required at some sellers, but typically it's not.