Which world does chapter 37 argue is superior to heaven, and for what reason?

Chapter 37 makes a strong case that the earth-world is of profound importance and is better than heaven. It argues that heavenly pleasures are temporary, and one falls from heaven after their merit is exhausted. In contrast, the earth-world is the unique place where one can access the science of the oneness of Brahman and the Self, which is the means to ultimate liberation. As the chapter states, even though life on earth is fleeting, a person who offers every action to God can attain a permanent place of fearlessness, which is a greater achievement than the temporary joys of heaven.