Battleriff is an amazing platform for dueling on multiple card games - Hearthstone, Magic The Gathering Arena, Shadowverse, Gwent, Artifact, Eternal.
There are different tournaments every day from which you earn Riffpoints, which is the Battleriff's currency. They can be spent on different goods in their market. Here you can find more information about the ways to gather RP. You can spend them on Amazon, Battle.net, Stean giftcards, gaming equipment and others.
The amazing part is that you earn points not only when winning, but also when losing. So there is no good reason not to join Battleriff.