>> Thats not going to help much against enemy missiles fired at the ship from long distances
How is distance a factor?
Energy disperses with distance and more-so in an atmosphere.
Think of your flashlight or even a pointer laser.
And at long distances the atmosphere does all sorts of things to it like refraction.
This says it will be limited to about a mile. It says its major benefit is low cost per shot, defensive missiles are very expensive.
The intended use of the LaWS is ship-defense against drones or small-boat attackers (whether suicidal or not); the LaWS at present is not designed to engage incoming missiles, large aircraft, ships, or submerged objects.
..... If tests go well, the Navy could deploy a laser weapon operationally between 2017 and 2021 with an effective range of 1 mi (1.6 km; 0.87 nmi).
Laser Weapon System