the reason is not the $$.... you can get 1 for $10
it's time saved... just add 10min to a regular shower, you walk out a new man..... 10min you'd spend on driving to the barber.
it's like changing the car oil.... 15min and it's done.... 15min you'd need to drive to the lube shop, followed by wrting up the order, watching shit TV in the waiting room or flipping thru magazines dirtier than toilet.
60F - why heat up the entire house while you can just heat up yourself with a light jacket.