The batteries are for all the noisy assorted toys the 'friends' and relatives buy for them. They no longer work because they bashed the f**k out of them, and they think just put new batteries in it and it will work!
Well NO! It doesn't work because you brought the damn thing in the bathtub and threw it off the deck 2 dozen times you idiot! Of course the batteries never make their way back to the remotes, or are ever found again!