I only say with regulations because I don’t want people forcing kids out there. But adults who want to do it as a job, totally up to them. Just be safe.
I believe it should be considered a business like any other. With protections for both the client and the provider. Eliminate the legal and policy barriers, so providers can market, advertise, screen, get healthcare, unionize, etc as they see fit for their business model.
My gut says the Australian model is the best framework thus far. Ideally government owned brothels only, with mandatory unionisation to give sex workers the best say in their own working environment. Privately run brothels simply can’t be trusted to obey regulations.
Not-for-money sex isn't a crime, generally speaking. I don't see why sex-for-money ought to be, provided it occurs within the same moral/legal boundaries (involves consenting adults, not children, etc.) -- beyond that, I'm not sure regulations wouldn't result in their own abuses.