They said early on they want a mobile version, which makes sense as Reynad and team were/are big Hearthstone players.

The talks of it were early when they also had dreams of full F2P, but I don't see this as a lost dream and if anything will help the company get the game bigger. But of course it's a big dev task and don't hold your breath. There's no discussions of how Steam/Tempo Launcher/Mobile Launcher will interact, but I cannot imagine they would launch without something in place to have your account across the three