I expect it must be put in something that can bring it close to its target to be effective. O(n²) power drop off for electromagnetic radiation is tough to beat at a distance of kilometers.

O(n²) power drop off only applies to a spherical emission. Focused power drops of much more slowly.

You can get a way smaller constant, but the area of a cone still drops off as O(n²) with distance. You would need collimination to beat that, and even then, there’s atmospheric dispersion.

I suspect the key is definitely in its focusing mechanism that allows for high powered bursts to be relayed to its target with relative efficiency.