According to the philosophy presented in Chapter 8, why is a life spent only on worldly activities considered a waste?

Chapter 8 of the Sai Satcharitra argues that a life dedicated solely to worldly activities is a wasted opportunity. The text states that much of life is consumed by sleep, restlessness, childhood play, youthful passions, and the infirmities of old age. It questions if the purpose of being human is merely to be born, breathe, and live a long time. The chapter strongly suggests that if one's existence revolves only around the four activities of eating, sleeping, fear, and mating, there is no fundamental difference between a human and an animal. According to the philosophy explained in Chapter 8, the true and unique duty of human birth is the pursuit and attainment of the Supreme Self (Paramatman), and failing to do so makes the entire life an exercise in futility.