What is the significance of the swan analogy in Chapter 17's discussion of Shreya and Preya?

In Chapter 17, the analogy of the swan, or Maral, is used to illustrate how a wise person chooses the spiritual path. The text states that just as Shreya and Preya are blended in life like milk mixed with water, a swan is able to drink only the pure milk from the mixture. Similarly, those who are courageous, intelligent, and wise can discern and cling only to Shreya (the path of salvation) while rejecting Preya (the path of worldly joy). This analogy emphasizes that the ability to make this distinction is a mark of wisdom and that the true purpose of human life is to be like the swan and choose the good over the pleasant.