Re Mario's bump fire video, that guy completely misses the point. The shooter wasn't going for pinpoint accuracy of a single target, he wanted to spray as many bullets as possible at a large crowd of people. And as that guy inadvertantly proved, that's really the only point of a bump stock, and there's no real legal reason for it otherwise.
Either way, banning them makes sense, but also won't make a dent of a difference on gun related deaths as a whole.