But why is this possible with fake currency but not with real money? I don't understand this and it seems like bullshit to me
I don't know how much more I could break it down for you bruv.
The store is owned by the store owner, the store owner makes money by taking a cut from every item sold, and since it's real money, taxes and laws apply.
Once the item is sold, the store keeps a record of who is allowed to use the item, other stores obviously do not have this record.
This item can be anything, a full game, additional content, a wallpaper, or fake currency. The store doesn't discriminate what it sells, as long as it gets a cut.
So now the consumer has a record of fake currency from the store;
this is where the store's involvement ends wholesale.
Now with this record the consumer contacts the manufacturer, and says "I want these items you are offering on your own store, I have this much currency".
The manufacturer then unlocks these items for you and
keeps its own record of this happening.
Now wherever you go where the manufacturer is they can see, "yes, we have a record of you having access to this, go ahead"; no other stores are accessed for this, it comes purely from the manufacturer.
