More dangerously, I think that would inevitably lead to space being the battlefield. Since that area doesn't need any more shrapnel orbiting at 17,500 mph; it seems an idea best left to the drawing board. The cleanup required will make clearing mine fields seem like dusting the living room.
Starship's in theory targeting something like a million bucks in fuel for a launch. For a military that spends more than that on individual missiles, that's peanuts.
It's fueled with methane and oxygen, and its size is known.
It can't be, say, $50m/flight in fuel for the same reason a 747's flight can't be; there's not enough space for that much fuel.
Also, fuel is just part of the cost of a rocket.
Sure. But if you blew up a 747 at the end of every trip, it'd be a small part of the total cost, not a major part.
Starship's reusability makes it very clearly not like the other examples you cite, yeah? There are lots of scenarios where the US government would pay, say, $10M to deliver a payload somewhere fast, but not $250M.
Near earth orbit will be a field of debris until gravity takes over.