My early car has the tethered footrest. When I have passengers they ask "what the hell is this thing ?" I say: it's footrest for you. They say: how does it work ? I say: I don't really know.
What is the practical position for it ? I sit in the passenger seat and try different positions and I cannot make sense myself. Can someone show a picture of it being used as it should ? I suspect this why many got chucked.