Arcadian! That's a new and useful term.
About the time that I got the Morten's Neuroma and started rehabilitating my feet and getting barefoot (a SN/FRN thing that many here were playing with) throwing out damaging shoes, I got into my India spiritual thing. Bending working on feet for hours at a time and the desire to be more immersed in what I was studying and practicing got me to stretch into those sitting positions. I enjoyed it and found benefits beyond.
I am more comfortable sitting basically such for long times than sitting in chairs, especially conference chairs. I think it is better after adapting to it. If I've got back support, I'm very comfortable.
What slowed me down in the first place, was a couple of rear-enders decades ago. Now, I'm finding ways to eradicate the systemic problems caused instead of listening to my chiropractor, but I do stop in on occasion. I had some bad posture habits from younger years, too.
The sitting positions do help those damages, the lower back pain, etc., but there is more to it.
As my feet aligned the rest changing to more healthy, I realized that the bones don't support the body as much as the muscles support the bones. I'm working out the band around the waist into the crouch.
Then a couple of weeks ago, I noticed that my knees were pointing in because of musculature reaction to the more healthy stance. So. I'm stiff and sore today after experimenting with various squat exercises to get the glutious maximus to pull back the knees, before I develop knee problems from walking. Posture in health is fascinating.
So, yea, and I'm doing things to improve it all. It has been slow and complex to repair my slouch issues and bad habits that accumulated for many years. I also have a problem with regimen. I also squat with both feet flat on the floor, third world style, which is getting more and more comfortable. I can do it for up to 10 and twenty minutes sometimes. The cross legged thing is relaxing, associated with just shutting down the mind and disappearing into...well.
Jbee