Backbends are to be felt more than expressed. The other postures can be expressed and then felt. Like in meditation each person has to feel backbends.
B.K.S. IyengarAsanas maintain the strength and health of the body, without which little progress can be made. Asanas keep the body in harmony with nature
B.K.S. IyengarThe light that Yoga sheds on life is something special. It is transformative. It does not just change the way we see things; it transforms the person who sees.
B.K.S. Iyengar