Oh god. So many reasons.
Okay. First off. It’s hilarious. As @fireinthepriory mentions, it’s the unknown. Yes, you get some genitalia photos. And some “shock” images. But beyond those.
You see some amazingly funny and interesting things. Not only from the people you get stuck with, but some videos that people make with it all. Take this video for example (Mostly safe for work). There are blogs like Catroulette (See the pun? CAT roulette, instead of CHAT! Har, you wouldn’t believe what they have). There are some interesting and funny experiments people do. If you’re a Redditor, there’s even a sub-Reddit for it, here.
Okay. Beyond that.
This may be a skewed perspective since I am such a socially inept guy (with plenty of social anxieties..).
But we’ve become a society in which we avoid talking to strangers, we’re afraid of them being dangerous, and our for our wallets and our “no no zones”. We go to work or school, we go to the store, we go home. We talk to our family and close friends, and that’s about it.
Not many people can answer this question: When’s the last time you struck up a conversation with a stranger on a bus, or at your workplace, or at school?
Hell, 6 months of living here, I’ve had one brief conversation with one of my neighbors.
Chatroulette gives you a chance to experience humanity beyond your immediate family and your 5 close friends. Sure, it’s not like you’ve having deep connections with these other people, but it’s a start. And it’s a safe opportunity. The worst that can happen is either the person presses F9 (To get connected to another user), or they show you a picture of their penis. They can’t steal your wallet, or stalk you, or stab you.