According to Chapter 16, why did Sai Baba, being a perfect being, take on a physical body?

Chapter 16 explains that although the Guru is the 'King of Yogis'—stainless, imperishable, and beyond attributes—he takes on a physical form for a compassionate reason. The text explicitly states that He has 'taken this body for the sake of helping others, to uplift the poor and lowly.' Essentially, He dons the 'cloak of ignorance' in order to effectively impart knowledge to the ignorant and provide sweet, guiding instruction to his devotees. His physical manifestation is an act of grace for the benefit of humanity.