See but you keep talking about the game from the perspective of someone who cares about skill and already cares about being skilled.
Hearthstone has a casual mode. Hearthstone has Tavern Brawl with a free pack every week. Hearthstone has avenues where people who can’t recognize how skilled they may or may not be- or, more importantly, don’t care to yet because they’re aware of their limitations- to play the game without a sensation of pressure and still make progress until such a time where they’re ready to experience the ladder anxiety that comes with Ranked mode.
Duelyst throws you into the deep end of the pool which, again, is fine if you are already concerned about being skilled and proving yourself with limited resources, but a lot of people don’t want to prove themselves with that particular challenge. They just want to build a decent collection or get those cool cards first before they even think about Ranked mode.