I feel like discing down is a very important stepping stone on the way to learning good form, line shaping, developing snap, identifying unnecessary overlap, course management, i also feel it will help define your style so that you can find the molds that fit your style and maximize your potential with less effort.
That said, to take it as gospel can be a mistake for some.
Some people use it as an every now and then refresher course type thing. Some do it once and never feel the need to do it more. Other people are just gifted and could never articulate to you how and why they do what they do. The last group mentioned there make up the vast majority of pros imo. I know feldberg is a teacher and a coach, so in particular he doesnt fall into that category.
I see DD as a driving range or a practice green, its as useful and productive and insightful and educational as you make it. Or its dull and boring and not for you.
Additionally some players learn differently and not all "tried and true" methods are going to make an impact but in general i feel like its the best place for someone who has played casually or semi competetively and seemingly hit a plateau, to start from and re engineer their game.