My son is only 18 months so I have not really had much chance to explain Santa and the Easter Bunny becuase he is too young to understand. He also doesn't seem to have any fear of monsters and such, which is good (however he was scared of the giant Dora, Cosmo, Wanda, and SpongeBob at Kings Island yesterday). I don't really see any benifit in having kids believe in fictional characters such as Santa other than it provides them with some entertainment and excitment. I also don't really see a detriment to it either.