Good and decent people can afford to spend a dollar or two to spend a penny, but not so for the primitives. I would pay money to use a clean restroom while out and about. My reason is the same as that of truck stops that charge for their showers- it keeps out the vermin.
The only modern pay toilets I've ever seen in my life were in Union Station in Chicago, when I was about ten years old. There was a whole string of pay stalls, and at the end, a "free" one, apparently as required by law.
The "free" one was a fetid stinking mess.
I had to piss, but safely held it in until we got back to the LaSalle Street Hotel.
There were pay toilets in the socialist paradises of the workers and peasants, but I dunno what exactly one was paying for, as they were just holes dug into concrete, and workers and peasants had bad aims.
<<<never dared use one; just observed them.
There was always a fat old carbuncled
babushka sitting in a booth at the door, who collected the fee.