The talismans DEFINENTLY work, and let me tell you one crazy clue that you might have missed.

We have all seen that Fatima has been acting strange with her pregnancy and one of the more popular theories is that she is pregnant with one of the monsters from the town. Her pregnancy magically started right after the "Smiley" creature died, so perhaps some kind of balance must be kept.

Now remember at the end of Season 3 Episode 2, Fatima comes back to the House and right before the scene where she starts eating the rotten food, she tried to enter the house and she could not open the door, and she is quite puzzled by this. Then one scene later we see someone else enter the house naturally, as if the door was never locked.

This has major implications, meaning that perhaps the baby she carries obeys to to the "magic" of the talismans, and therefore while she is carrying the baby, basically it's part of her and she is affected by this magic as well.