What part do the frequent anecdotes play in the book Beowulf?

In my opinion, the frequent anecdotes are in this book mainly because it was not written as a modern book.  Instead, it was passed down from generation to generation of story tellers before it was ever written down in the form we now have.

In the days when this story was being told, story telling would have been a major source of entertainment.  There was nothing else to do on long winter nights.  So you would not want your story to end quickly.  Because of that, a story teller would put lots of anecdotes into a story to make it last longer.