I'll go out on a limb and state that virtually nobody outside of a moderator has given any thought to how much space a topic like Word Association, et al, will take up. I certainly didn't give it any thought. Now we are much more keenly aware. Perhaps before someone wants to initiate a topic akin to W.A., TPBM, Where Does everybody Stand... - we should consult a mod? Of course new people register all the time and that may not be practical, but it's a thought.
Aside from the space issue and general annoyance by some, I have found that the fun topics are a non-threatening way for newbies to integrate themselves into the forum. A lot of people don't know anything beyond the VFT that they just got for their birthday, or whatever. All computer savvy aside, reading about issues raised by the highly experienced folks can be intimidating. While a newbie just wants to keep their plant alive, they have absolutely no idea of the enormity of this hobby. There is no way they can contribute to discussions of identifying the various cultivars of D. spatulata, for instance, not knowing much more than they have a sundew. This is where the fun topics come in, while newbies slowly learn.
Additionally, the fun topics have been a great way for some people to meet others and cultivate friendships.