Maybe because it was permanently plugged in, imagine the cables you’d have for permanently charging at home. There’s also a facility to have cars moving in train layouts now, without the scalextric groove.
Still got those heavy duty extension leads haven’t you 😂
I know there’s some roads (Norway?) where theres stretches of road you can charge as you drive, which is technically cool, but I guess, it’s nothing more than fantasy fr anything similar in the UK.