I don't mind so much the soulbound aspect, it's more the way they are done. The reason they can't make rewards tradable is because they devalue existing assets too much. The mistake they made with soulbound is thinking they now can print way more of them which also devalues existing assets like crazy. There is simply no reason right now to hold real cards. Only keep the soulbound ones and milk rewards is the meta right now. There are zero reasons for existing or new players to buy real assets in the game.