Can you explain the two different motivations, 'Kamya' and 'Nishkam', for studying a Guru's biography or other spiritual texts?

The preface in Chapter 0 explains that both Guru biographies and other spiritual knowledge texts are used in two ways: with desire (Kamya) and with a selfless mind (Nishkam). The Kamya approach is when one studies these texts for worldly gain, such as achieving prosperity or seeking the removal of worries, calamities, distress, and diseases. In contrast, the Nishkam approach is undertaken for the ultimate spiritual goal of liberation from the world and freedom from the cycle of birth and death. Chapter 0 is clear that Nishkam Guru service will always be considered superior, regardless of the specific form it takes.