If you agree that war and war machines aren't good for the economy than let me ask you this.
If every state had it's own professional army, how would that effect our economy as a whole? We would be sinking more and more resources into weapons of war. We'd have an internal arms race happening in our own country. That's more and more government and more and more lost resources. When does it end? Does it ever end? I, for one, hate weapons; but I know that, as of right now, they are required for security. I would much rather see a world with weapons decreasing than increasing. Can we ever get to a point where killing each other is unnecessary?