I'm not quite sure about how Tom "Mountain" Murphy, the ally, works. His card states that I should "Ignore the Stamina cost of all tasks". If it means that it's useful solely on monster tasks like monster Flying Polyp, it sounds that this ally is almost useless. But, if I interpret it as if he would prevent me from losing Stamina from adventure effects like Unnatural Habitat ("Terror: Lose 1 Stamina") or even Stamina costs from failing an adventure, he becomes too powerful, I think.
What's true? Is there a middle ground?