It has as much economic value as Aircraft Carriers do. It might be an economy in itself, creating a demand for food and other necessities which must be procured from somewhere, generating demand. It must also be supplied by weapons, clothing etc (not sure how durable they are in that world).

But you're right that it can act as an enforcement agency, a tax collector of sorts. Or maybe an extortionist: "Pay up or we destroy your planet!".