While that NIH article lists interesting phytochemical components in the avocado pit, I've only seen one source that states it's actually good to eat - Jeff Primack's website (https://jeffprimack.wordpress.com/2010/09/15/specific-foods-reverse-specific-diseases/
). Primack is a martial arts teacher who has moved into the new age/nutritional arena with his book, "Conquering Any Disease". One other website advocates doing this (https://seetucsonhomes.com/healthier-you/avocado-seeds-amazing-superfood/
), but only offers empirical evidence from their personal experience. The NIH article does make it clear that there's a lot of potential goodies avocado pits might be, specifically some cancer fighting compounds that could be extracted from them.
I've seen Jeff Primack in person where he made smoothies with avocado pits, and I don't disagree that they can
be eaten...but should they? Seeds usually have protective chemicals that discourage digestion (phytates and tannins) and some can be removed with soaking, but without a better understanding of those chemicals (or at least some in-depth scientific analysis), I might skip on eating them regularly. And at the very least, you're gonna need a kickass blender like a Vitamix or a Blendtec.