The knowledge about Yoga asana as physical posture is a common mistake by beginners.
Here in Cobra pose, the hands’ support for spinal extension overcomes the erector spinae and multifidus which are the actual muscles. If the student is using the big joints like shoulder, elbows, and wrists for the back bending, the smaller joints of the vertebral column will be loose the structure. Muscles will be overstretched and lead specifically to the instability of lumbar vertebral facet joints.
Same for advancing the lotus pose, the feet are taken in reverse direction. This is not the actual pose by lower limb muscles but by the upper limb muscles. Hence there is no “Sthiram Sukham Asanam” from Patanjali Yoga Sutras.