Actually dangleman, you are incorrect on that. You can more than make your balls bigger. And chicks DO care about ball size, AFAIK. Certainly not as much as penis size, but the idea of having some nice hanging nuts slapping her ass while you impale her is something a lot of chicks enjoy.
It’s an added effect, yes, not really necessary, but why the hell not have it? This site is about penile obsession, when you get down to it, so why not go all the way and include the entire area down there? =)