To confuse and disable the suspect/target/enemy. Your eyes can't adjust to a strobe the way they can to a regular light. So what ends up happening is it ruins night vision, while at the same time being so quick a flash as to not allow you time to really see. However if you're behind the light it acts like slow motion, You can still see what's happening but only a frame every few tenths of a second. If you're gonna use it in a tactical situation be sure to aim for the face, otherwise it's useless. But I assume common sense would tell you that.
