According to the text, what are the dual benefits for an author who writes a detailed poetic Guru biography?

The preface in Chapter 0 outlines a dual benefit for the author of a detailed poetic Guru biography. Firstly, by studying and writing the biography, the author performs a high form of Guru service for their own spiritual progress. Secondly, the author gains the merit of serving God in humanity, referred to as 'Jan-Janardan,' and performing public service. This happens when other devotees use the author's work to study and perform their own Parayans, thereby helping them achieve the purpose of their lives. This creates a virtuous cycle benefiting both the writer and the readers.