Its not a panacea in preventing trafficking but for the workers that want to be there it doesn't criminalize them, and the market for establishments are pretty competitive and great for patrons. Game of Thrones can't even compare, while many tourists corral themselves over to one street in Amsterdam due to its marketing campaign even though there are whole countries that are way more awesome.
The std testing is the most attractive part of these systems. "Tolerant" and "Decriminalized" places do not have the capability of offering that. Let alone everywhere that outrights criminalizes workers and/or Johns.
I think the population health should be a prong that is weighed heavier. Regulated systems do that. If there is any coercion of the sex workers then spend resources enforcing that and providing avenues just like anybody else in a domestic abuse relationship.