If women are kidnapped, coerced, tricked, or held against their will, we already have laws against kidnapping, rape, fraud, and slavery. So why extra laws? It’s there to protect women that are in no way coerced, tricked, or imprisoned.
You make a good point. Prostitution is there anyway and it hurts nobody. So why not make it legal? If some girls got beaten up forced or tricked, we have laws for that already namely against battery, rape, and fraud.
My biggest concern is women in poor country. I am sure they are not happy with males available there. Especially women in Afghanistan where they can get stoned. I am sure 90% of beautiful girls there honestly would rather go to europe even though they ended up becoming sugar babies rather than a wife. I think having a “wife” status is overvalued.