It's all about getting their hands on foreign currency. Similar systems were ubiquitous across Eastern Europe, with the DDR's Intershop probably the best known

It's all about getting their hands on foreign currency. Similar systems were ubiquitous across Eastern Europe, with the DDR's Intershop probably the best known: you could even take the subway across to Friedrichstraße in East Berlin and shop at the platform without needing to go through passport control. https://en.wikipedia.org/wiki/Intershop https://en.wikipedia.org/wiki/Intershop