It’s not like a central bank or national currency which you could sell at the airport or a kiosk at the mall for a real exchange rate

They were prisoners, what good would that money do for them in the first place?

Like I said, they got paid and they got amenities. They also had recreational activities (sports, a swimming pool), orchestra, library, movie theater, etc.

To recap: you went from believing in gas chambers, to believing that they were starved / worked to death, to finding out they got paid for their work and were treated far better than any other POWs in the war.

And there's still so much you don't know.

But I'll end it here because I don't think you're interested in learning about what really happened. As your first comment showed (starved/worked to death), you want to be attached to the mainstream narrative.

FWIW, I'm not even saying the Nazis were good people; I'm just saying that there's a lot of lies about them and what really went on in WWII.