I'm using a "button" as a proactive approach to dealing with burglars, the same way that a gun would, pushing the "non-confrontational but just as effective" angle more than anything.
My whole reservation to using a gun for defense-against-home-intruders is that you have no idea what the other guy is doing or has to defend against you. And, really, the "defense" part assumes that you get the jump on said burglar. Do you really want to take that gamble?
Well in that case, a gun would have been useless, too. I don't think anything could really be considered "useful" in that scenario, as that's pretty much worst case.