From
https://www.airpilots.org/file/666/t...g-stalling.pdf
In the past it has been considered acceptable to use rudder to pick-up any wing drop whilst teaching the signs of the full stall. This technique is dangerous and has been cited as one of the causes of more than one stall/spin fatal accident. Use of the rudder should be restricted to preventing any further yaw, should any develop. If significant yaw/wing drop occurs whilst trying to teach the full stall signs, recovery action should be taken immediately. If all of the full stall signs were not taught before recovery proved necessary, then it will be necessary to give an additional demonstration.
So it seems it may have been considered
de rigueur at some stage.