ok, i think, again, you're conflating stuff. maybe you should be more explicit about what you want to do.  the whole point of VSS is to do what collections do.  i don't believe bagginsbill has explicitly said, "don't use collections," but it does seem obvious.  if you look in the VSS thread, towards the end somewhere i think he mentions Matmatic support.

in case you aren't aware, because i think many aren't, VSS does much more than work with skin.  it comes with a default skin shader, but that's just one possible use.  at one point bagginsbill was talking about selling it with tons of other default shaders.

so, once again, Matmatic is optimized for making a single material.  like a skin shader, a wood shader, a patterned glass shader, etc.  VSS is made to manage materials.  if you are managing materials with Matmatic, you are trying to get it to do something it wasn't optimized for,  and that VSS was optimized for.

no, Matmatic is not the equivalent of face_off's realism kits.  neither is VSS.  face_off's realism kits are something like VSS, but more like Parmatic.  and really, they're all just different.  but, either way, just to say, while i believe bagginsbill said you could distribute materials made with VSS, Matmatic and Parmatic, i do not believe he said you could distribute tools based on those utilities.  and face_off's kits are tools, not shaders.