The teachers on the podiums up at the front is a creepy psychological hack, the recorded chanting they play while you meditate is hypnotic programming, the 2 hour video lectures of the great leader convincing you of his religion being your only stimulation, the bowing and mindless chanting from the regulars being passed off as "optional for first timers."
Many of the people there mentioned they go several times a year, with that glassy eyed obsessed stare. At least one person mentioned they had moved their home to be near the group.
I tried to skip a session because I didn't get enough sleep and the management came and got me out of my room. That's when I knew it was time to leave.
Also, if you leave early, you get excommunicated and blacklisted.
The point of all this is to make you unquestionably loyal to the group and to become an evangelist, which is how these things become so popular.
The danger of cults is that if you go for long enough you can permanently lose your identity and self respect. It's probably not actually possible to 100% master the skill of meditating painlessly, which undermines your confidence and makes you more determined to achieve the enlightenment they promise, which exposes you to more brainwashing and makes you more submissive to the great leader, etc.
They do at least provide a source of protein and the food was pretty good.
The technique itself is pretty useful, and after the 4 days of silent nonstop meditation reality felt really weird and everyone in the outside world looked like an impulsive idiot being emasculated by their smartphones. This feeling lasted a few days and then wore off.
I'm sure the effect lasts much longer if you do the full 10 days. I'm pretty sure you would get that same effect going through any very intensive and stressful course and avoiding anything fun or distracting, and the culty brainwashing stuff is totally unnecessary.