According to the Wikipedia article about Flannery O'Connor,
[h]er writing reflected her Roman Catholic faith and frequently examined questions of morality and ethics.
The article's section about the characteristics of her work adds,
She felt deeply informed by the sacramental and by the Thomist notion that the created world is charged with God. Yet she did not write apologetic fiction of the kind prevalent in the Catholic literature of the time, explaining that a writer's meaning must be evident in his or her fiction without didacticism. She wrote ironic, subtly allegorical fiction about deceptively backward Southern characters, usually fundamentalist Protestants, who undergo transformations of character that, to her thinking, brought them closer to the Catholic mind.
The article does not answer the following question: Does Flannery O'Connor's fiction argue for the importance of religious belief for its own sake or for its possible benefits to society?