This can also be an indication of the iron not being sharp so that excessive force is needed to get a shaving.
For me, I can flick the knob to get rid of the backlash, which can be 3 or 4 flicks (I guess), but once the backlash is out, it takes more effort. On some planes, I can get enough friction with a finger tip to make actually move the blade. On other planes, it might take a finger and a thumb. I suspect what you are seeing with Paul is him flicking the knurled knob a few times to get rid of the backlash, but then it takes so little movement to actually move the blade that you’re not seeing that part.