Since this months theme is about "Expanded Universes" I'll argue that games and the stories or shows created about them to be a planet... Consider that a planet's pull is proportional to its mass. So, more spin-off material makes a larger, more engaging experience.
A proper story line, and enough questions in need of answers are reasons I like turning to the serial novels etc. of an exceptional title. The trash aside (Books all for profits and catalysts to sell more copies,) good material is like a mini-history lesson, drawing a parallel line over top a story, and succeeding to expand on things that dialog, cut scenes and character development alone could fail. As a learning tool, the expanded universes bring lore and mythos to an otherwise linear experience of what you see is how things are.
As horrible a movie Street Fighter: TLOCL is, I can sum up the point of this post using it as an example. Because it was made, my experience of Street Fighter IV is made better because of it.
With more backstory, you're sure to immerse yourself further in a game.