It had an upfront cost (where all the competing card games are F2P) and a cost to play as well as to acquire cards, which put a lot of people off. It is also a

It had an upfront cost (where all the competing card games are F2P) and a cost to play as well as to acquire cards, which put a lot of people off. It is also a more complex game than say Hearthstone, but I think the success of MOBAs proves that complexity is not an inherent barrier to popularity.