The arguments for legalising brothels are, as far as I know, that it makes it easier for the madam to call the police if a client becomes obstreperous, that the public health authorities can demand that the prostitutes are regularly examined for sexually transferred diseases and that both the women working as prostitutes and the madam would have to pay income tax.
I know that the Netherlands are re-considering the idea, but I still feel that the women working in legal brothels are better off than those working in countries where prostitution is illegal.
Sweden brought in a law some years ago now that made it possible to fine the men who used prostitutes. Unfortunately, it has not solved the problem, as the working girls pick up a pizza and "are just delivering it" to the man who called them!
Here in Denmark, where brothels are illegal, the expensive women work in high-end hotels or night-clubs, the majority work on the streets and have little or no protection, and the poor girls who have been trafficked from Asia, Romania or wherever are mainly forced to live in appalling conditions in illegal brothels and are being held as slaves.
Legalising brothels probably won't do these poor girls one jot of good, but it might mean that the police could concentrate on finding the illegal brothels and that the licensed establishments would rarely need to occupy police or court time.