It's interesting all right. But, three things it really desperately needs - a way to skip the tutorial, an owned card filter for the deck-builder, and a difficulty rating when challenging duelists.
If you've played hearthstone, you know how to play this game. The deck-building is where the new mechanics lie, but that's not tutorialized. Plus, players may want to restart if they encounter early game breaking bugs (like when the shop ate my initial 200 cash and didn't give me a pack). And... you've got an iron-man mode. People are going to restart the game, no need to run the tutorial multiple times.
For the filter - when you are starting out you don't really have that many resources to work with. But you do have enough cash to get a card pack. Which means you can start re-tooling your deck a bit... if you could only find what cards you actually owned. There's no reason to show me all the cards I could eventually own, when I only have enough resources to maybe craft 1-2 cards, and only about ~35-36 cards to my name. I don't need to see the whole list. Just the cards I own so I can modify the starter deck a little.
As for the difficulty rating - Most open-world free-dueling games of this type (yu-gi-oh and duelmaster's game boy games) grouped duelists into diffrent areas, with the harder duelists being in the later areas of the game, or in specific settings (like a turnament). While the arena kind of does this... the map is very open at the start. So it's very concevable you can encounter a duelist that's just too powerful for you to face at the start.... right at the start. It'd be nice to have some warning before fighting someone you aren't equiped to fight. While, also, giving you some feedback on how good your deck is once you start beating harder opponents regularly.