You know, I just gotta say first, I just got back from a tiring day at work. I was pissed off on the way home because of the crowd in the buses and trains.
Then I came home to read this and instantly felt relief. Society is all work and stress, and reading these philosophical matters is a great break.
So thanks @gavvet.
Anyway, I can't really say much about the purpose of death except that we aren't supposed to perfectly know the purpose.
People like to say, "Things for a reason."
Well, sometimes that reason is that we aren't supposed to know the reason.
That's it. Death no matter what, will always be a mystery for every living person has not crossed over yet.