Why sitting cross-legged can sort u physically, spiritually

Often it is funny how people pretending to be seated still will wriggle their toes or feet. They are extremely disturbed at sitting cross-legged on the ground.  But it's an ancient Indian practice now trying a comeback. It's treated as an exotic pose.the lotus or padmasana. But it should be   natural to us. Sitting on the chair could be unnatural, disconnected na?
The other equally neglected pose but which is celebrated by ancient rishis is siddhasana. For women the version would be siddhayoniasana.
Here is why sitting cross-legged works even if only at the physical level. According to Swami Niranjanananda (in his comment on siddhasana) : Meridians in the feet are stimulated and they are connected with the visceral organs eg the stomach, gallbladder, liver, spleen, kidneys, etc and all these poses have important roles in purifying the blood. "