halogen spotlight would transmit in the infred range creating a hotpot, literally. When a cabaret dancer would walk through the audience you could feel the heat and on a cold night she was, not just a vision of beauty, but literally radiated warmth.
I do not think gentlemen clubs have started doing this, but it would cut down on heating costs and they could direct the heat towards the dancers encouraging them to venture into the audience for more tips and reduced exposure, for lack of a better word. This can increase engagement without direct encouragement from staff, less liability. Think herding cats instead of commanding dogs.