What is the deeper significance of writing and studying a Guru's biography, like the Shri Sai Satcharita, in the context of serving the Guru and the community?

The significance is twofold, creating a symbiotic relationship between the writer, devotees, and the Guru. According to Chapter 0, a Sadguru takes two forms of service through books, one of which is having biographies written by devotees. By writing a detailed biography, the author performs Guru service. Simultaneously, when other devotees study and perform Parayans of that work, the writer earns the merit of serving "God in humanity (Jan-Janardan)" and public service. This act of communal study allows the entire congregation of devotees to accept service from the Guru and achieve the purpose of their lives, thus building a strong, spiritually-focused community.