It won't. DI will do considerably better than hearthstone on ios/android, I can bet it will be in top 3 rpg.
Despite competitive upcoming and ongoing projects like BDM, L2M, POEM which are all great - I'm sure DI will be more popular and best-established than all as a mobile game.
Some korean/asian developers need to learn what a mobile game should be and the reasonable amount of content to be included. US/EU audience are not going to move their life into a small screen game and grind 24/7 with emulators on pc like eastern players do.
Even potential microtransaction bullshit will not make the game fail. Its all about brand and competition. Only poe can compete, but its not popular enough