Providing support services to those who desire to exit the sex trade broadens the options available to those in prostitution. It increases their agency by providing an alternative path, that is their choice to take or not take.
I agree with that, your original post was phrased in an odd way, I dont think making buying illegal is a great solution as making that part legal is also harm reduction.
assumes no agency, does your assumption assume the prevalence of independent people that are not trafficked?