He defeated the purpose of not using manual at the end of the video. There is a clue he would do this in the photo at the beginning of article accompanying the video. Notice on the right of the photo where the exposure compensation dial is circled and has an arrow pointing to it. That is the clue that in the video he would tell you don't use manual then tell you to "essentially" use manual. Contradicting himself.
If you are in aperture priority, and we assume you manually selected ISO, then you are not using manual. But the moment you start fiddling around with exposure compensation, you are (in effect) using manual. At that point you have set aperture, ISO and now you are changing shutter speed with the EV dial. That is manually setting exposure even if your mode dial is set to A. Same if your mode dial is set to S (Tv on Canon). You just set all three sides of the exposure triangle. Same as manual, but you used a different dial to do the same thing.
One can argue that A or S mode may give you a "correct" exposure quickly in some situations. It might even make exposure settings quicker by getting you in the "ballpark," but then you you have to fine tune with the EV dial. And when the subject changes, but the light falling the subject does not, manual works best. Related to the last sentence, his focus tip that uses the face to meter for exposure only works if all the face reflect light like a gray card. Going from a light-colored face to a dark face changes exposure if you meter off the face, but the light falling on the faces does not change.