This is a complex novel. It basically concerns early America where slavery was just beginning (17th century). It also has a melding of races and they are all competing with one another. Toni Morrison mentions the Portuguese, Africans, Dutch, Native Americans and mixed races. If you look at it from this multi-cultural perspective, then you can say that the multiple perspectives that Toni Morrison uses fits her content. Form and content match.
Another benefit of having multiple perspective is the insight that no issue is monolithic. Moreover, something so complex as slavery will have various views as well. Finally, the multi-perspective approach shows that each individual also has their own story to tell. Hence, we read about Florens, Messalina (Lina), and Sorrow, to name a few. In a word, a multi-perspective approach offers an efficient way to tell a story through various voices.