It is untrue that fiction is nonutilitarian. The uses of fiction are synonymous with the uses of literature. They include refreshment, clarification of life, self-awareness, expansion of our range of experiences, and enlargement of our sense of understanding and discovery, perception, intensification, expression, beauty , and understanding. Like literature generally, fiction is a form of discovery, perception, intensification, expression, beauty, and understanding. If it is all these things, the question of whether it is a legitimate use of time should not even arise.
There's always moral instruction whether the writer inserts it deliberately or not. The least effective moral instruction in fiction is that which is consciously inserted. Partly because it won't reflect the storyteller's true beliefs, it will only reflect what he BELIEVES he believes, or what he thinks he should believe or what he's been persuaded of. But when you write without deliberately expressing moral teachings, the morals that show up are the ones you actually live by. The beliefs that you don't even think to question, that you don't even notice-- those will show up. And that tells much more truth about what you believe than your deliberate moral machinations.