Definitely pro-chitchat. As others have said, and I agree, it is a place for FIRSTers to just lay back and have fun. It's also another way to get to know other FIRSTers when you really can't in real life, or on a daily basis. See their personality, get to know what their opinions about certain topics are.
Honestly, if there are threads that should not be in Chit-Chat (aka, inappropriate) there are ways to deal with it. Simply by ignoring the threads, or just adjust your portal settings. It's as easy as that. It seems to me that CD has become way serious and opinionated lately. I'm getting worried
So yeah, PRO CHIT CHAT!