Puccini set the stage for many operatic composers/writers to come.  The music is absolutely beautiful.  Aesthetically, I feel it is most definitely worthy of preservation.  Also, at a time when cultural "blending" wasn't exactly common and/or welcome, Puccini told a potentially controversial story which was very important.  Also, these characters are human.  Puccini's music made them even more so.  The music, with its rises and falls and its tonal changes, created the emotions and the intensity felt throughout the opera.  This story with the aide of Puccini's music solidified a story of the time creating a piece of history that has been passed through the ages.