I use these for their complexity and randomness. Great to twirl, fold spin and mutilate for ground textures, bump maps, etc. I am not advocating them as a background or anything. Too many default bryce textures being used in my opinion. Would like to see more realism, this is just how I do it. Maybe I'm wrong? I don't use post production, I try for it all in Bryce. I know it can be done.