What Can A Warship Mounted Laser Weapon Do?

A U.S. Navy destroyer can generate a lot of electricity to power a laser weapon with, but what can the state of the art production models actually do? 

They do have military utility, but it is mildly underwhelming, and it isn't clear how much time it takes to damage or destroy one target before moving onto the next. 

If the rate of target destruction is potent enough and the strikes are powerful enough (the two points are not unrelated), these active defenses could make warships much less vulnerable to a variety of attacks (except torpedoes and mines) than they are now.

The U.S. Navy's Arleigh Burke class destroyer USS Preble is now armed with a High-Energy Laser with Integrated Optical Dazzler and Surveillance system, or HELIOS. Preble is the first of the service's ships to be equipped with HELIOS, which is a 60-kilowatt class directed energy laser weapon, and is also the first to have any such weapon integrated with the Aegis combat system. . . . 

HELIOS, as its name indicates, is a multi-purpose system. It is powerful enough to damage or destroy certain target sets, such as smaller drones and boats. In this way, it offers something of a limited substitute for the lost CIWS and provides a layer of defense against these targets, which can be particularly threatening to ships like Preble when operating in swarms.

The system can also act as a "dazzler" to blind or confuse optical sensors on enemy ships and aircraft, and optical seekers on incoming missiles and other munitions. When used in this way, HELIOS can potentially throw off incoming weapons or limit an opponent's general situational awareness and surveillance capabilities.

Lastly, HELIOS has its own optical sensors, which are primarily used to spot, track, and cue the laser, but that can also be used in a secondary surveillance role.

From here. 

Note also that 60 kilowatt isn't really all that much power. It is equivalent to 80 horsepower and there are street legal cars with more than 12 times as much power. A Tesla Model S has more than 1,020 peak horsepower. There is no good reason that a naval warship shouldn't be able to field a 750 kilowatt directed energy weapon that would be far more effective than a 60 kilowatt directed energy weapon.