Is it practical to let a user choose between the USD and EUR balance? You always have to deal with price rises and falls, which could turn out to be a disadvantage for a customer. I've never seen that in a sportsbook before. Maybe it's better to just use 1 currency, which the user can choose and then don't let it change. I think there will be some confusion otherwise.
ya.ya.yo!
Some are more accustomed to USD, some EUR so it's always nice to have something extra. While the wagers are in crypto, the values are better remembered in fiat.