Don't worry! You will learn that.
In general they are a currency as Foodpoints, but you only get them when you pay real money or buy them from someone who did.
And you can use them in stores like this one for example:
https://kofk.de/shop.php?mode=shop&s=88
For one Fairy Coin, you can get a whole set in one color there (or the monthly set).
But you can still decide when you finish the knuffel ;)
I will still have that fairy coin and the food points by then and you can tell me what you would prefer :D