I'm a little ambivalent myself. As said many times by many monks, PM is about Perl; there are an infinite number of choices for every kind of discussion already available.
However, there is a social dimension to a community, even of geeks discussing their favorite language. Almost all of us feel the need to go off-topic now and then. The CB is an outlet for that, but is really ephemeral. I almost never participate because it's essentially real-time only, and I just don't click often enough to keep up.
zentara's idea about limiting an off-topic forum to monks with a certain XP level (say 1 to 3) is really good. That would help keep it a community thing, not just another free-for-all. In fact, it should be invisible to the outside world. Maybe it should be excluded from search, too. Also, it could be a time-limited thing, anywhere from a week to a year. But more than the CB's 3 minutes.