She can be! Mostly she wants to see men fall to ruin, so she dangles what they want right in front of them and then gives them impossible tasks to earn it. Men constantly try, but their efforts are usually in vain.

And I can't spoil the ending! Bat Man was set up with a seemingly-impossible task, after all. Louhi expected him to fail. The ending is only so great when you hear of all his struggles first.