What are the different motivations for reading a Guru's biography, and is one considered better than the other?

According to the provided text, Guru biographies can be used in two ways: with desire (Kamya) or with a selfless mind (Nishkam). Kamya usage is for worldly gains, such as achieving prosperity or removing worries, diseases, and other calamities. Nishkam usage is for the higher purpose of attaining liberation from the cycle of birth and death. Chapter 0 explicitly states that Nishkam Guru service, which includes the selfless study of these texts, will always be considered superior to service performed with desire.