Based on the source, what distinguishes the Shri Sai Satcharita as a 'grace-filled' book, and why is this quality important for a spiritual text?

The preface in Chapter 0 describes the Shri Sai Satcharita as a 'grace-filled' (Prasad-janya) book, which sets it apart from works written solely on scholarship and intelligence. This means it was created not just from intellect, but with Guru's grace, inspiration, and as a divine gift. This quality is considered crucial because, as Chapter 0 notes, a spiritual book without these attributes will not leave a lasting impression on seekers, nor will it inspire their faith or trust. Being 'grace-filled' ensures the text will be cherished and studied daily by devotees.