Thank you for enjoying our game! The 'Draw Card' button represents the action at the start of each round, where you need to draw two cards first (or three cards if you selected the 'Little Bear Talent' at the beginning of the game). These drawn cards are then added to your hand for the next round of combat.
Due to time constraints, we weren't able to implement all the feedback mechanics for the combat interface. We'll definitely work on improving and polishing this in the future. Thanks again for your kind words and support!