Private Torrent Sites

I find private torrent sites very annoying. What's the point?

Usually, the private site will have rules that encourage sharing. But, the number of potential peers is smaller because it's limited to the registered users of the site, which doesn't sound like an advantage to me. The other supposed benefit is that there's less chance that one of the peers is a spy monitoring the torrent swarm. I have doubts about this benefit. I can't imagine a site is going to ask for more than an email address from anybody who registers.

Actually, I think the point of private torrent sites is just elitism, plain and simple. It's like belonging to a private club. It makes people feel special.