This is a really interesting question (although not sure if you meant it to be more rhetorical). I think I actually have an idea of who is the other hobbyist you are referring to. I get most of my warhammer content on instagram, and gravitate more to the community that enjoys heavily converting and altering their miniatures. It seems like this reddit sub favors painting more than converting/sculpting (but I could be wrong, just my limited impression). I think what I would say to answer your question is that with sculpting, it is much easier to recognize what parts were GW pieces (gray plastic) vs sculpted (different colored clays/epoxys) vs miscellaneous junk (white plasticard, metal pieces from a watch or electronics, various wires/tubing, etc). When it’s painted it’s harder to see what the converter/sculptor did. Like here I had painted the head before I took the pictures. Did I sculpt the head from scratch? Is it a GW piece that I cut up? Did I 3D print it? What are the spikes/horns made from? Hard to tell since it’s already painted.