I think there is absolutely nothing wrong or immoral with it. I think as long as its between two grown consenting adults, it's nobody's business but their own.
I actually think since sex is part of what makes a human healthy, it's perfectly natural for companionship and intimacy to be a service just like any other.
I do have to say that I'm speaking of men (hiring and providing) in general here.
I do not believe that the government has any business regulating the private matters between two consenting adults. Period.
As far as morality is concerned... lol. All of our "moral authorities" have proven themselves completely unworthy of being any authority about morality at all. It's a personal matter and we all have our own values.
I'm curious as to what your views are about it. Has anyone dealt with any shame, no matter how small, over the decision to hire or provide and how have you dealt with that?