I think it'd be nice if we could know the time it'd take a ballistic missile to reach a target, before we actually launch the missile (from a submarine or launcher or whatever).
That way, if we have multiple launch platforms in different places, we can coordinate their launches at the right time such that the missiles will arrive at the same time.
That way, if we have multiple launch platforms in different places, we can coordinate their launches at the right time such that the missiles will arrive at the same time.