I think limiting one's guard game only to the positions that protect the head/control posture is just too limiting. He uses an example of someone getting KTFO in deep half guard, but there are probably more examples of people taking very little damage in deep half guard and being able to score a sweep or chase the takedown. It's the type of position that has to be played aggressively to keep the guy using his hands to base instead of punching, but IMO disregarding all such positions because they can go wrong if you fuck up, well ... I just think it would make your guard game more predictable and easier to shut down.
Crawl atop me ... and meet your doom!