Can writing biographies of public figures or philanthropists be considered a spiritual service that grants salvation? What distinction does the text make?

The preface in Chapter 0 makes a clear distinction. Writing biographies of thinkers and writers as a form of public education is considered a worldly service. While it may contain philanthropic elements, it is ultimately limited by space and time and is often rooted in self-interest, therefore it 'does not yield spiritual fruits.' Even writing the biographies of many saints is considered a partial service. The text posits that the most certain service for attaining the ultimate spiritual goal is to write the biography of one's Sadguru and study it with unwavering devotion, a practice that is distinct from worldly or partial forms of service.