Because it much more harder from algorithm point of view, and i tend to use it that way , maybe i need to pay more attention to corner case with high density, it looks really cool except absence of normal. BTW, you can try tweak "g" as specular factor, g close to 0 resemble diffuse Orven-Nayar surface, g close to 1.0 is fancy high specular surface (imagine surface covered by layer if tiny glass spheres as road signs paint).I looked for heaviest density with sharp edge. You wrote about "soft detail edge"? Why?
About http://blenderartists.org/forum/atta...1&d=1326425934, it touching sphere, just illusion because wrong shadow probe (i hope it fixed in last patch) and overall shadow-less light setup, you hardly can guess actual white "blob" distance from sphere w/o proper shadow. Maybe some luck with random generator make additional illusion.