Questions

I had several burning questions about the style in  which the book thief was written. My first was on the short little interruptions in the text. Are these meant to give the reader more information, or truly for the fun of death? If it is for death's enjoyment, will they mean something greater later in the book?  I was also looking at the point of view it was written in. I am still pondering why Mark Zusak picked Death. Why Death? Why not Hans or Mama?