What is the purpose of the frame story technique?

The result of inserting one or more small stories within the body of a larger story that encompasses the smaller ones. Often this term is used interchangeably with both the literary technique and the larger story itself that contains the smaller ones, which are called pericopes, "framed narratives" or "embedded narratives." The most famous example is Chaucer's Canterbury Tales, in which the overarching frame narrative is the story of a band of pilgrims traveling to the shrine of Thomas a Becket in Canterbury. The band passes the time in a storytelling contest. The framed narratives are the individual stories told by the pilgrims who participate. Another example is Boccaccio's Decameron, in which the frame narrative consists of a group of Italian noblemen and women fleeing the plague, and the framed narratives consist of the tales they tell each other to pass the time while they await the disease's passing. The 1001 Arabian Nights is probably the most famous Middle Eastern frame narrative. Here, in Bagdad, Scheherazade must delay her execution by beguiling her Caliph with a series of cliffhangers.