If we're shooting in good light, then choosing "P" or "M" is not that much of an issue. If the conditions are marginal and/or the subject is moving, then knowing the mechanics of exposure becomes essential to be able to get any decent result. It goes beyond the issue of camera settings. Under "good" light, you don't need to think about light diffusers, reflectors, fill, separation lights, etc. In poor conditions, you absolutely need to know how to manage the light(s) to extract a good image.
So the question to me is, under which conditions are we shooting? If I was to give a workshop to beginning photographers, I'd try to arrange for a bright, semi-overcast day near some light-colored wall which can be used as reflectors. Then we can leave the camera in 'P" mode, and concentrate on composition, framing, and the like. If the DOF becomes needed either to be shallow (to minimize background, for instance), then we'd change to A mode and play with large, medium and small apertures. If we want to explore motion blur, we'd switch to Tv or S mode and play with the different shutter speeds and see what works. If the subject was predominantly dark or light, then we could explore the role of exposure compensation to "correct" the exposure for the subject matter.
On the other hand, if we had challenging light conditions, scene dynamic range greatly in excess of the camera's ability to capture, and/or the need to compensate for fast motion, then there is no choice but to pick the best combination of metering mode, shooting mode, focal length, and accessories (tripods, lights, light modifiers) to allow us to achieve our objectives.