Can you explain the significance of the grinding stone and the author's justification for writing about devotees' praises as mentioned in Chapter 40?

In Chapter 40, the act of Sai Baba grinding grain at his stone is presented as a foundational inspiration for the entire book. This deed sparked a strong desire in the author to describe all such acts to destroy sins. The chapter further justifies the focus on devotees by stating that God (Hari) loves it even more when someone sings the praises of His devotees than His own praises. To lend authority to this claim, the author directs any doubters to the Bhavishyottara Purana, where Tripurari (Shiva) makes a similar statement, suggesting the entire composition is divinely inspired.