There are several differences between reading or hearing a story. In the way distant past it was much easier to just hear stories because there were no tools to write with and more importantly no one was literate. Many times when hearing stories it can cause differences between the original story and the versions of the stories that are told after. Reading does not typically encounter this problem as it allows for the original words to be published and prevents any alterations from being made to the text. Many early stories were just passed down through the word of mouth and much like Gilgamesh, it leads to many different versions of the story. Many times those who publish their own version of Gilgamesh there are several differences between the story due to their respective interpretations.
Hearing and reading stories both allow the reader/listener to use their own creativity to imagine themselves in the situation that is being painted for them. Many times reading stories allows for a more personal connection to the story rather than hearing a story as told by someone else. Reading stories allows the reader to try and interpret the text that is in front of them in their own way which can lead to many different pictures being painted for everyone. When hearing stories, those that are listening to the story really do have to rely on the person telling the story to paint the picture for them. But, when being able to read a story it allows the reader to reread portions that confuse them and allows them to paint a clearer picture.