It denies the element of chance. It brings order to God's cluttered, capricious universe. Plot serves the story, but plotting serves the author. I mean the balance of tone and structure, scene and sequel, conflict and resolution. I believe pace to be the thing which separates a novelist from a short story writer.
Pace is the heart of plotting.
It is simply knowing when to tell what so as best to heighten drama. Plotting is more important for those of us who write children s stories than for those who write for adults. I think I'm a good judge of this because I write for both. You laugh, but I stand by my comment. When you write for adults you have all this down-time.