I think I finally know the reason for praying!!! Beyond what it does for us personally in building our relationship with God. Many times I have wondered what it does. God can do anything he wants! And he knows what we need before we ask! And he loves us deeply and moved first to reach and heal us! So I never understood what it did - although I knew it did something powerful because of the Bible images like Israel winning a battle when Moses' arms were lifted up.
But something hit me a few days ago. We have a whole universe watching the battle between good and evil on this earth. One of Satan's major claims against God is that he takes away freedom and controls what people must do. Our prayers give God permission to move here - in a world Satan still claims as his own! - without that judgement standing against him!