RE:RE:RE:RE:RE:RE:RE:RE:RE:Lookey here!
My guess would be that a "challenge" is a custom wager someosome one would create "Broncos beat the chiefs today " - 100 Fancoins. Then someone can accept that challenge or not. Browse through other wafers or create your own and tie a certain amount of coins to the bet. The store would have to offer some quality products in order to get people to purchase the fancoins in app. Imagine you would start off with a house amount and daily "quests" or "engagments" could reward you with additional coins.