The high directionality of lasers makes them great for communications- your energy is concentrated in a small spot... but that means no one will see it unless you are intentionally targeting them. The divergence of the laser used to communicate from the moon was roughly 20$\mu$radian- thats like shooting between New York and San Francisco and hitting an 80meter wide target.

Beams for interstellar distances would likely be far more collimated. If you transmitted a 1550nm laser out a 10meter diameter telescope with diffraction limited divergence that would be ~8nano-rad... That beam transmitted from Proxima Centauri would be 644,000 km wide- just 4.5 times the diameter of Jupiter- not a big target, and you need to hit that target where it will be 4.2 years in the future.