"All art is quite useless" is one of Oscar Wilde's famous sayings. In looking it up, I found a letter in which he elaborates on the point. He offers an analogy: "A work of art is useless as a flower is useless. A flower blossoms for its own joy. We gain a moment of joy by looking at it. That is all that is to be said about our relations to flowers." You can Letters of Note link to see the letter as written and more of the transcript.
There has long been a debate over whether literature should simply entertain or entertain and instruct. Most of us read fiction for fun, not for information. However, The Business Case for Reading Novels contends that there is utility is what has been deemed "useless." It expands a bit on the research presented in the following paragraph:
Over the past decade, academic researchers such as Oatley and Raymond Mar from York University have gathered data indicating that fiction-reading activates neuronal pathways in the brain that measurably help the reader better understand real human emotion — improving his or her overall social skillfulness. For instance, in fMRI studies of people reading fiction, neuroscientists detect activity in the pre-frontal cortex — a part of the brain involved with setting goals — when the participants read about characters setting a new goal. It turns out that when Henry James, more than a century ago, defended the value of fiction by saying that "a novel is a direct impression of life," he was more right than he knew.