I think its a symptom of our western culture where we can try things out without the necessary 'pre-conditions' or prerequisites taken care of.
If your comfortable sitting cross-legged for around 2-3 hours upright, no back support, and dont have knee pain after a session like that, also have no stress and no psychological issues... then perhaps its for you. Some people seem to benefit from it... others, it makes them 500% _more_ crazy than before.
I also hear its great for criminals whose minds are so 'set' in their ways its hard to mentally break through to them. some videos have been made about it: https://www.youtube.com/watch?v=phHib5VaCeE
I think for lots of the HN crowd, we are type 'A' learning personalities who can endure a lot of pain pushing through to achieve knowledge etc... however, pushing through against your own inner psyche is usually a bad idea, you want to gradually go up against it, and use bodily medidations like yoga to work with the Trauma. Sitting in a static position for 6-8 hours and doing intense absorption technics like the OP Article, can be a recipe to set off a bomb in your nervous system. I think a better solution for a lot of people is to see a therapist to talk about mental health (finding a good one is hard in itself), and then add in sustainable exercise routines to stay healthy.