Drivers need to apply reasoning to the process. Outdoor temperature and how far you can drive at reduced speed need to be in the equation. Automatic transmissions are cooled by engine coolant. They are also warmed at start up by the same process. Slow, low load operation helps distribute the heat more evenly through the transmission.
I have a transmission temperature gauge for my vehicle which I pay close attention.
To be honest a problem might be heavily reduced by investing in a quality fully synthetic transmission fluid. It makes perfect sense if you live in a cold environment. Of course, most people won’t do it and they would ruin their cars following stupid advice.