Never played the game. Didn't even know the concept was discussed in it.
And, on a relative scale, yes it's not hard. It's certainly far easier than sending a ship to trade with someone that far away. In fact, nearly all of the problems of interstellar travel go away in this case - the basic fact is that not having to slow down when you get there (and not caring about the safety of any occupants in the vehicle) makes the issue massively easier. You don't have to worry about fuel, or shielding, or long-term biological maintenance. Just accelerate it up to speed and have a few final maneuvering thrusters on an automatic system.
Of course, if you are traveling around you've solved those problems, and can if you wish launch from within your target's solar system. Which makes targeting much easier, though you may give yourself away as you get the weapon up to speed.
On the other hand, hiding isn't as hard as you might think, especially if life (but not sentient life) is moderately common. Most of it even makes economic sense: Keep your transmissions low powered and focused so there isn't much leakage, and keep the atmosphere fairly clean. That will make it nearly impossible to tell an 'inhabited' system from a 'life-bearing' system from any distance.
Of course any aliens could be proactive and be striking at any life-bearing system, although that's a lot of wasted effort. Still, even then if we were to move into space-based colonies and asteroids we could hide fairly effectively. (Again, communication would be the biggest leaker, but economics and the square cubed law help the hider out.)