I think that it can be a great a way to see how the world is affected by your actions, and how the world ultimately affects your missions.
Also, it could be a way to lead the player into using ammo a bit more sparsely. For example, Thorton can go into a mission with guns akimbo, shooting anything that moves, and setting off alarms all over the place. However, that would put the player all over the news, thus making subsequent missions a lot harder.