According to Chapter 17 of Sai Satcharitra, what is the fundamental difference between Shreya and Preya?

Chapter 17 of the Sai Satcharitra explains that Shreya, the path of salvation, and Preya, the path of worldly joy, are as different as light and darkness. Shreya is described as the form of discrimination and pure Knowledge (Vidya), while Preya is the form of lack of discrimination and pure Ignorance (Avidya). The text states that he whose mind runs toward Preya falls away from his true self-interest, whereas the wise are never deluded by it. This fundamental opposition is the core teaching introduced in this chapter.