If entered voluntarily, I do not see a moral difference.
I do however recognize that there still is a societal stigmatization when it comes to sex work (there is also stigmatization when it comes to "menial" jobs such as cleaning toilets, but less so). This stigmatization to me doesn't appear to have a rational footing, but either comes from "traditional" and/or "religious" values (same as opposition to homosexuality), or from confusing voluntary sex work with involuntary sex work (as I often see in self-proclaimed "feminist" perspectives).
All in all, a lot of societies seem to be in a state of cognitive dissonance, where voluntarily selling your body for sexual gratification of others is illegal... unless you make a movie out of it, or do not actually perform outright sexual intercourse (strippers, dominatrixes).