Sure, you can break systems. That doesn't mean that they aren't useful! In many cases a system will see the same boring input many times over. People are often willing to be a bit flexible and help out when it happens to misread something. The fact that you can intentionally break systems like that, and that you can break them in a particular direction, like making them always think there's no danger in an image, is really worrisome.
Our work shows that your autonomous car won't always work well; that its vision system has some systematic error which we can characterize now. Adversarial attacks show that someone can intentionally make your car see a lane, whenever and wherever they feel like it, and drive you off the road. It's a whole different ballgame, and the language of attack and defense really fits well.