What are the two different motivations for studying a Guru's biography, and which one is considered superior?

According to the source material in Chapter 0, Guru biography texts can be used in two primary ways: with desire (Kamya) and with a selfless mind (Nishkam). The Kamya approach is for worldly goals such as achieving prosperity or for the removal of worries, calamities, distress, and diseases. In contrast, the Nishkam approach is undertaken for spiritual liberation from the world or freedom from the cycle of birth and death. The text explicitly states that Nishkam Guru service, regardless of its form, will always be considered superior to service performed with worldly desires.