Ok dude, this is like miners being paid in “scrip” only to be redeemed at the mining companies’ stores. It’s just “good boy coupons” and yes, it is a currency, but you had to spend it where you were. 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...it wasn’t Deutschmarks.

“The first known use of Holocaust money was in the Lodz ghetto in Poland in 1940. Over the next five years, the Nazis introduced currencies in concentration camps and other ghettos in Germany and occupied Poland, Czechoslovakia and the Netherlands. Each camp or ghetto had its own currency — with unique denominations and designs — to be used only within its gates.”