How is serving a worldly Guru, like a politician, different from serving a Sadguru for spiritual growth?

Chapter 0 highlights a critical difference between these two forms of service. Serving a worldly Guru, such as a politician or historian, by writing their biography is considered a service of a worldly nature. Its importance and benefits are not eternal but are limited by space and time. The text notes that this type of service is often rooted in self-interest and therefore does not yield spiritual fruits. In contrast, writing the biography of a saint or one's own Sadguru is a form of spiritual service. When done with a selfless mind (Nishkam), it is considered a superior practice that can lead to salvation.