I created that for the zombies to have something to do. And I needed an interesting way to score points. Also I think that this passively helps in the forest not being almost entirely zombified by you.
So the darkshroom faction basically does nothing and sits there waiting to be removed- but other factions can benefit from this meeples not being able to be zombified by you and also can move them away from you.
But yeah I recognize it is a bit confusing so any ideas are welcome