Why are the biographical collections by poets like Mahipati and Dasganu Maharaj considered less suitable for a focused 'Parayan' of a single saint?

According to Chapter 0, while the famous poets Maharaj Shri Mahipati and Shri Dasganu Maharaj wrote valuable collections of saints' biographies, such as 'Shri Bhaktalilamrut', these works are not ideal for a 'Parayan' or 'Saptah' dedicated to a single saint. The preface clarifies that the biographies within these collections are often very brief, sometimes spanning only two or three pages. This lack of comprehensive detail makes them unsuitable for the in-depth, devotional study of one particular saint's life that a dedicated 'Parayan' requires.