All of us are prostitutes. We sell ourselves to companies and corporations for a weekly paycheck. There's no difference other than the work activities performed. Every job carries inherent dangers with it and you must take care to remain safe in your duties.
Making anything and everything illegal only opens the door for black market scum to take it over and profit in a clandestine way. Negating the payment of lawful taxes to central authority and assisting in draining vital resources with no return on investment.
Legal, let's call them companions, would be beneficial to society in ways not considered by the upright prudes. It could very well eliminate rape and/or prevent divorce by offering an outlet for sexual tensions to those who would otherwise have none.
Even Jesus had a whore in his company. He may have even married the girl for all we know. Talk about handing out a shining example of forgiveness.