Why is the earth-world considered more significant than heaven for spiritual progress?

The earth-world is considered profoundly important and superior to heaven because it is the primary place for attaining ultimate liberation. As explained in Chapter 37, heaven is merely a place for sensual enjoyment, from which one inevitably falls after their merit is exhausted. The pleasures there are no different from earthly ones. In contrast, the earth-world, despite its fleeting lifespans, offers the opportunity to realize the oneness of the Self and Brahman. Chapter 37 emphasizes that even a momentary life on earth, where every action is offered to God, can lead one to a place of fearlessness, making it unlike any other realm.