There already legal in Australia, since they are legal in mine and a few other states. Hardly anyone smokes pot and there is no crime connected with prostitution or drugs. Men or women who work as prostitutes, have to register for a business number ABN, and tax file number and be over 18. They all use condoms or dams and have regular check ups.
We even have legal medical staffed injecting rooms. Having them has stopped IV drug users, leaving used fits on streets, or O.Ding in alleys, etc.