Sure, until someone says "hey can we stick this on a truck and use it against cars?" "Hey can we stick this on the belly of a plane and use it on a building?" "Hey what happens if we do a flash of this at protestors?"

Could definitely be used in an offensive capacity. I don't think it'll be a red alert 2 style prism cannon, but I do think it can be used to gain air superiority. With a long enough runtime, this thing could definitely take out a plane.

That said, it's pretty tame. We can already take out planes with flak cannons. This is just more efficient.

There is no such thing as a defensive weapon.

You might be tempted to say "what about a missile shield?" but such a thing allows the owner to act with impunity with levels of violence we arguably haven't seen since 1945.

As a real example of this, the only reason a deeper conflict didn't develop with Iran this year was because Iran demonstrated they could overwhelm the various layers of Israel's missile shield and Iran seriously depleted the various munitions used by those air defense systems (eg interceptors, THAAD) and those take a long time to replenish.