I agree. Plus it's useful, when viewing a member's profile, to see how engaged they've been in the forums.
I generally ignore those.
Structuring visible rewards for achievements is a fundamental motivator. So setting these different levels gives people a slight boost in status to reward them for participating in various ways. People will say they don't care. Chances are that they do.
I have to give whoever put the "Kitty" reference in there kudos for the blast from the past, for giving me the opportunity to take a playful swipe at Myr, and for bringing up this whole dialog. It was a good thing.
My personal opinion is that the rep point levels are probably deserving of something a little more staid (and boring). Those are points you get when people like your stories or your posts, so at some level, it represents an acknowledgment of a good effort. I think that the levels for forum posts can and should be more playful, since that's the social venue (or one of them) for this site. Then again, I've been wrong before.