I don't remember saying that one type of point wasn't the other... that a pressure point couldn't be a vital point or a dim mak point... I was focusing on usage more than nomenclature. Three major areas of "vital points" are the solar plexus, gastroneimus plexus and vagus nerve structure in the neck and brachial sinus... which are primary nerve bundles and primary nerves. Most of the pressure points work off the branches of those areas.
The Dim Mak "delayed effect" points work off the circulatory system and the autonomic nervous system. Many of the points which cause organ damage are related to the vagus nerve structure and it's proximity to the area struck... which is why the angle and depth of strike are important.
Without getting into a lengthy discussion, I would suggest that the reason the information was taught through kata was to teach a student how to strike at the correct angles, with the right "tool" and from the proper position to effect the strike correctly. Ed asked for an explanation of the differences in the points, and for the most part, they are application differences used for different purposes. Anybody reading more into what I said than what I said is guessing... I'm sure plenty of you out there have medical training that has a different concept of how the body works than the dim mak concepts, but the dim mak training wasn't designed to treat illnesses... it was designed and used to cause "system shutdowns" in the body... i.e., organ damage, embolisms, etc.
Unfortunately for medical science, everything isn't able to be "reverse engineered". There is "life" and there is "death", and if science had all the answers, we could dig up Albert Einstein and "reconstitute" him for more studies. If science had all the answers to why the body dies, they could "fix" it... as it is, they can "delay death" in most cases for some period of time, but not always and not consistently.
Of course there's no "raw data" on dim mak, but I would suppose that the success rate of DM strikes would be comparable to the medical professions ability to reverse it... and that would be from "finding a victim" on the street, diagnosing the condition, and then correctly treating what was wrong with them. Of course that's just supposition, but the chatter here is always that DM doesn't work, and there's no data that shows it either way... but it's an interesting study, and a pretty good set of practice skills to have... just in case they do...