[3.5] How does Superior Literacy work specifically?

A player of mine is running an Illumian and has the racial trait Superior Literacy which is described as: "Illumians are always literate, regardless of their character class. Speak Language is always a class skill for Illumians, regardless of class."

I'm having trouble figuring out how this trait would come in to play in game. Can someone specifically explain to me what this means in an actual game situation?