Consuming the benefits of having a woman sexually interested in you is a very different skill from creating that interest in the first place. So they would just pay to skip all the steps that they are bad at, thereby never learning them.
This is a poor analogy because apples and apple juice don't involve social dynamics. I can easily see a man who is experienced having sex with women through prostitution being more confident flirting/being intimate with real-life women. And confidence is a large part of "creating that interest."
If you're paying someone to live out those fantasies, you're probably not going to experience "normal" sexual relationships.
Plus you'd be (temporarily) alleviating the pain and frustration of loneliness, which is a huge boost in morale and will bring hope. That being said I've never tried a prostitute, although I've considered it in times of loneliness for the same reasons above.