Lois, I think facilities in undesirable parts of a city can be rented for a lot less money than more desirable venues. They may be out to "witness" to the poor, uneducated, vulnerable people who live there. I think it most likely that the grimy pounds and pence are their chief motivation for anything they do.
1963 was my first assembly, and my first trip to New York City. I was a 16-year-old hillbilly girl who had never been anywhere. I was so excited. I actually had a 6-year-old boy hang around me as if he had a crush. There was also another boy who sat with me and was very sweet - and good-looking. Those were the days. But, of course, as time went on, things changed - a LOT!