How does the text differentiate between worldly Guru service and service that yields spiritual fruit?

Chapter 0 draws a clear distinction between worldly and spiritual service. Worldly service, such as writing biographies of great politicians or historians, is acknowledged as a form of Guru service, but its importance and fruit are not eternal; they are limited by space and time. This service is often rooted in self-interest and therefore does not yield spiritual benefits. In contrast, writing the biographies of saints is a form of service that does yield spiritual fruits, although it is considered partial and may not be sufficient on its own to reach the ultimate spiritual goal.