Look out Sebastian! More spiders headed your way! :-) While my original thoughts regarding the use of these beasties during my games centered on having them popping out of terrain, I see that they can do something else, if need be.
There have been many games where there was simply no way for me to effectively get at archers ensconced inside buildings, or at least standing on walls. Very frustrating. At least now I have something that is guaranteed to get up there and go after them!
This is just about it for the regular spiders. I need to sculpt myself a spider queen and some broodlings at some point...