>>96525056
Absolutely true. In any real system, there will be vibrations. Either from nearby machinery, people walking around, being buffeted by wind, distant traffic, or any number of other sources. Even just the ambient temperature of the environment can lead to unavoidable thermal motion. These vibrations will be transmitted to your beam pointer, and cause the beam to jitter slightly. This will make it harder to keep your beam at one spot on your target. In extreme cases (like long range shooting in space) it might make it uncertain that you can hit your target at all.

As your focusing ability becomes better and better, probably by going far into the ultraviolet or x-ray parts of the spectrum to limit diffraction or using low emittance particle beams, it becomes harder and harder to correct for the jitter relative to the ideal focused spot size. A long range beam may just have to deal with its focused spot of destruction wandering randomly around on its target - or, for very long ranges, wandering randomly around in the space near its target, hoping to trace across it at some point. Oh course when you get hit by enemy weapons, or even warmed up lightly by them you get thermal expansion and even more jitter.

The Hubble Space Telescope experiences vibrations in its solar panels when it rotates, leading to about 50 microradians of jitter which requires about 100 seconds before normal operations can resume. And properly functioning Hubble has precision of 24cm at 1,000km (telescopes are inverse lasers) with a 2.4m sized mirror. Test case laser of the same size, 600 MW at 1080nm, gonna be similarly (not exactly) limited.

Ultra long range lasers need to be big SUPER stationary fully automatic platforms to work at all, and even then are a massive headache at just at 1 light second, so much so that you'd only maybe bother using them as "coastal guns" for defense as missiles or enemies were incoming.