The headband had a dual purpose: to help The Old Gods and The Great Beasts. I think it says a lot of good things about The Old Gods' commitment to protecting the Earthly Realm that they got to Easton first. I agree that Easton may not have been the best possible choice if The Old Gods had a chance to choose, but I doubt that many mortals would have been able to take the overpowering compelling of both good and evil (and the subsequent life-essence extracted from Easton) without having serious consequences.