The texts mention that some collections of saints' biographies are not suitable for a detailed 'Parayan'. Why is that, and what makes a text suitable?

The preface in chapter 0 explains that while great poets like Shri Mahipati Maharaj and Shri Dasganu Maharaj compiled biographies of many saints, these collections are often not useful for a 'Parayan' or 'Saptah' focused on a single saint. The reason given is that the individual biographies within these larger works are not comprehensive or detailed, sometimes spanning only two or three pages. For a text to be suitable for such devotional readings, it needs to be a detailed, poetic, comprehensive, and famous work, like the Guru Charitra written by Shri Saraswati Gangadhar.