"This gun is godsend for terrorists. It is a gun that you can easily create at home, and it can be carried on planes and other high risk places without detection."
How is creating a low quality gun at home some kind of godsend? A high quality gun can be acquired quite simply anywhere in the USA. Even if you have some kind of problem with your criminal background you can acquire one at the right price. Or get someone else to acquire it for you. And you don't have to worry about detection with a small gun because it is easily concealable. You're free to walk out of the house and head to times square if you so choose.
I'm not sure why you'd think it is better than a bomb. Those are also easily made at home and can be made to look like pretty much any non-threatening object.