‘Why should Germans support poorer Spanish regions if Catalans object?’

Most commentary on Catalonian nationalism dwells on whether this is something that's going to have implications outside of Spain. How worried should we really be if the Catalans get a bit more fiscal autonomy or even independence? But the Catalan debate actually raises a much bigger question that goes right down to the essence of the eurozone as it stands, namely if Catalonia is unprepared to subsidize Spain’s poorer regions, why should northern Europe do so?