The question I would think is closer to the truth is. Who would benefit greatest from having a God? The answer is quite simple and profound.
1. The people who act as agents for God. The priest class. God is taught to us as an authority figure who dishes out reward and punishment when we are at our most vulnerable (after death). So to stay on the good side of God one must visit his/her house regularly and pay homage and a small donation (if one can).
2. The ruling class. Whether royalty of elected officials they need God to assure the soldier, during the time of war, that what they are doing is right and there will be no repercussions for their actions. Examples of this psychological manipulation is throughout the Old Testament. Also the doctrine by St. Thomas Aquinos and the justifiable war gives this weight.
The question is why doesn't your religious leaders point this out.
This flies in the face of the teachings of Jesus, who said love thy enemies etc.
