How does Voltaire make use of the literary particularities of the tale in his philosophical arguments against optimism and for reason?

Why did Voltaire chose to use the format of a tale to present the story of Candide, why did he chose to use a tale to present his ideas of the world, how he perceive the world as true love does not conquer and religion will not save you, more precisely to say is that true happiness of the heart can only be fulfilled when one can ignore all the worldly desires and troubles, to be totally settle down to cultivate the fulfillment in mind through simplicity? A tale by definition is a malicious story, piece of gossip, or petty complaint; a deliberate lie; a falsehood; a narrative of real or imaginary events; a story. (American heritage dictionary) These definitions seems to fit into Voltaire’s idea to present Candide more like a comic story then as a real life situation, due to the fact that the characters in the story had all went through many deaths and miraculously escaped from the misfortune and came back to life. All the seemingly impossible adventures of Candide in the tale were cre...