You're talking about opening gambit - Those are valid points. It would have been nice if we were able to get some basic AI into the game, but when we were getting to the point of designing the boss fights we knew we weren't going to get there. So we built these challenges assuming the player would use card costs to limit what can be played from hand. We definitely could have been clearer that the cards are played randomly (assuming the card's cost can be paid), so I can definitely see how the hero making bad moves could be frustrating. That's legitimately helpful feedback!
If you feel like giving the game another shot I'd love to know if thinking about using card costs to control what can be played from hand helps make the game more enjoyable for you. No worries either way, and thanks again!