Potters also have existed in all places and in most of history, and they have a category under occupations. So do servants, scientists, day laborers, and various sorts of farmers. Putting aside people's ingrained beliefs, sex work is just a collection of occupations. It has been a part of people's daily lives, influenced society, art, and law, and even religion, since time immemorial. The only reason I see not to give sex work a category is that people find it shameful. But people also find slavery shameful and we don't erase slavery here on Wikitree. And yes, these occupations are genealogically significant; none of us would exist today if not for the sexual choices of our ancestors.