Why is human birth considered such a rare and valuable opportunity that shouldn't be wasted?

The human body is considered an incredibly rare prize that, as stated in Chapter 8, is found only through "great good fortune and gathering millions of merits." The text emphasizes its value by noting that even great efforts, like those of Bhagiratha, cannot easily attain a human body; it comes into one's hand only by destiny. This opportunity is precious because, among all species, only humans possess the "ladder of discrimination" to ponder existential questions like "Where did I come from? Who created me?" Other species are born and perish without this self-awareness. Therefore, wasting this life is foolish, as there is no certainty of returning in the same form.