Never been in a situation where I had to, but it could provide a distraction long enough to either allow me to get around them and run, throw the first punch, or grab one of the weapons I keep beside my bed to use against them. I'm not a violent person, so ideally i'd take the first route. Even if it's only a brief few seconds of extra time, in a hostile situation every moment counts. So despite how childish it may seem, it's not about stopping the aggressor entirely, it's about buying enough time to gain at least the slightest advantage over them. If it achieves that end, it "works" as you put it.