It allows the reader to understand the reasoning of Gilgamesh changing. There are no changes in Gilgamesh as a person until Enkidu enters the picture. Obviously he is the reason for all eventual changes in the personality and manhood of Gilgamesh. If the belief and understanding of Gilgamesh and Enkidu being much more than good friends is present, then the understanding of why Gilgamesh changes in the book is also present. If Gilgamesh is just friends with Enkidu some change is possible, but not almost total recall as Gilgamesh does in the book.
People change more if there is sex involved and there is a deep relationship.
In order to make Enkidu happy, Gilgamesh has to change, and he does, throughout thier relationship. The Epic of Gilgamesh, the better understanding of the book reveals that, in fact, Gilgamesh does change from the beginning of the book to the end. The personality of Gilgamesh changes for three distinct reasons. First, Gilgamesh changes in the book because of his insatiable desire for immortality after the death of Enkidu. Gilgamesh wants immortality after the death of Enkidu.