Why Fanfiction is Good
1. All the universes of fandom are established and those participating know everything about it. In bandom, people know the band members, their songs, their personal lives, and history. There is no need for a writer to give this information because it is already known to the reader. Or, if the reader is new, they can find out pretty quickly because if a certain item is consistently brought up, it can either be assumed fact or googled to confirm.
2. Because the universes are established, this saves time for both the writer and the reader. Background and description does not need to be included because it is already common knowledge. The writer and reader can get right to the point of the story that uses their favorite characters.
3. It's an escape from the real world. Even if, as a writer, you're translating yourself entirely into a character, there's still a sense of escape because you're writing yourself as a character and then looking at the perspective in that way as opposed to your real life.
4. In addition to escape, it's typically easy to read and write due to the fact major literature elements aren't needed. In college, I had to read such time consuming, complicated books. Fanfiction let my mind take a break with the easy reading that I was familiar with. Also, it was fun writing opposed to academic.