Why is the earth-world considered more significant than heaven for attaining a state of fearlessness?

Chapter 37 presents a unique perspective, arguing that the earth-world is of profound importance for spiritual liberation, even more so than heaven. It posits that sensual pleasures are the same everywhere, whether it is Indra in a celestial garden or a donkey in a dung-heap. The critical flaw of heaven is that one's stay is temporary; you fall from it once your merit is exhausted. The earth-world, however, is the designated place for learning the science of the oneness of Brahman and the Self. Though life here is fleeting, it offers the opportunity to offer every action to God and thereby attain the ultimate place of fearlessness, which is a permanent state unlike the transient joys of heaven.