Why 'You guys figure it out' isn't a great method

This is a translated in-game comic from Lower. I recall a scene in the story where characters ask the player to command their battles. Of course, there's the 'You guys figure it out' auto or full auto mode... But it's not a great method because they act according to a thoughtlessly programmed sequence of actions. Replays at least remember and follow the commands, but this is just... In full auto mode, they first play a spell card. If it's the last wave, they go straight for the Last Word. In other words, if you can't defeat all the enemies in one turn, the battle gets completely messed up.