I caught my daughter most of the time she pitched. There were 2 reasons for this. First she needed someone to be a "parrot". By catching her I could see what the pitches were doing and listen carefully to what her pitching coach said, and then during her workouts between pitching lessons I could "parrot" back to her. I paid her pitching coach not only for the time, but for the information we could take out of there and I felt that I needed to catch her to make the most of that info. The 2nd reason was that it became clear early on that if she was going to be successful she would need to pitch 3-4 days a week. I knew that we could not count on some other kid being willing to give up that much of their time/life in order to allow my daughter to be successful, so I was the only choice. I have to admit also that I would not trade that quality time we had together for anything, I am finding that is what has been the most difficult for me since she left for college.
However I think the idea of having catchers available for a fee is a great one. My daughter was fortunate that she had someone available to her as much as I was to catch her. For various reasons such as health and ability to name a couple some girls don't have this option. I believe that anybody who does not see this as a good idea is not considering that everyone does not come from the same situation.
Lastly on catchers, when my daughter reached high school and began attending college showcase camps, I never caught her there. If need be I would pay for a catcher to attend sessions of the camps as well so that she could be there to catch my daughter when needed.