Good read and very good theory. I appreciate you bringing it up as it certainly is an alternate option for some who simply want to 'add mass' to their door panel which will change the sound of the panel when something hits it, and that's about it. This is just part of the equation of this exercise.
It doesn't go into the option of outer layer and inner layers being covered which creates a 'double glased' sound chamber scenario and contributes significantly to cutting noise levels down, or the other benefits that doing the entire metal panel brings.
This sound deadening day is about taking people from close to 0% previous experience (in a lot of cases) and bringing them to that 70-80% level in a rapid space of time. If they get bitten by the bug, then the physics of waveform audio and a whole host of other issues will be the next thing on their agenda. After this basic deadening exercise, things can get very complex, very quickly.
The fact I've picked Dynamat is because it's SO easy to work with as a novice and intermediate installer (the audience at this event) not brand alliance. There's better product out there, but it's deerer and much harder to work with.