I was wondering about that just yesterday. "What are the value of those coins?" I thought. There seems to be a mint (episode 3), and the guy who runs the whole thing (the central bank) seems to live out in the desert.
Who sets the value? Can anything be money? (let's forget about the intrinsic value of the gold itself for a moment.).
It seems that these coins are used within the community of the criminals themselves and the bank sets their value. It also seems that the community can pay for things with fiat currency or these coins. And it seems that one can exchange these coins for fiat currency too.
The John Wick universe is an interesting example to see the practical use of another currency in everyday use embedded in a world of fiat currency.
But what really got me thinking (I know, late to the party)... money can be anything. Anything that a community decides what it is. As the community becomes larger it becomes more valuable, but also it comes with more problems too (the USD as example).