Trim it down a bit, make it portable perhaps and you have a class of torture equipment that's in a league of its own.
Because this thing works instantaneously and over a long distance, people are going to be caught in the middle of it and have to endure excruciating pain for much longer than the few seconds it would take to dissuade them from proceeding with their plans.
What will this do in crowds: the most massive panic you ever saw in a large crowd because -everybody- will feel the same pain and -everybody- will want to go away immediately. Whether or not this happens after a few seconds or a few minutes [depending on who is pushing the button on the thing] a massive wave of panic is going to make people flee in every direction. This will cause numerous people to be trampled in the stampede.
In portable units, the beam will be focused on someone who will not be able to escape and who, in our time-honoured tradition, will be made to suffer the most unspeakable pain until someone gets bored and decides it's enough... for today.
The makers of this device should see their children placed in front of this monstrosity and watch them as 24 hours of the thing working on full power go by. It's cold, it's callous, it's heartless, yes it is. But they have to be shown how it will be used and what it does to people they care about. Because, as with all weapons that we invent, this too will be abused in the most heinous way possible by people without scruples who do not care about the suffering of their fellow man.
We have more than enough problems in the world today, the last thing we need is -yet another- way to inflict pain on one another. And I don't care about the less-than-lethal argument. It's in the same class as the 'but the terrorists' argument that the world is using to legally impose the most invasive intrusions into people's personal lives in the history of the species.