[DF] Why is the Prime Material Plane Important?

[b-dog]

I am interested in ideas for why the Prime Material Plane would be important in in a DF cosmology. There are so many planes like the Elemental, Divine Realms, the Hells, Astral, Ethereal, Outer Void and so on that it sort of makes you wonder why anything existing in this cosmology would even care what goes on in the Prime Material Plane because there is so much other stuff going on.

For me it seems that the Prime Material Plane is a place where wars are waged between the various other planes. And also the act of being mortal gives a chance for growth and development. Humans souls have no choice as they are placed into bodies at birth and during life they must decide where their souls will end up. Faeries like dwarves, elves, gnome and others decide to become mortal when they become bored of the Faerie Realm and experience life. But all in all, the Prime Material Plane provides more Free Will than other places of existence although it also results in death as well.

If you have any ideas then please feel free to post.