Hey there, future person, you've misplaced your iPhone 5. Some nefarious person is trying to break in and steal all of your naked pictures. Not to worry, you've programed Siri to self-destruct Mission Impossible-style after three incorrect login attempts. Boom.
Actually, I already do something similar to this using Cerberus on my Android. After 3 unsuccessful password attempts, my phone automatically takes a picture which gets automatically emailed to me. From the Cerberus web console, I can also "self-destruct" by wiping the phone, though without throwing off the shards of glass. Clearly iPhone is superior in that regard.
I can also send alarm and display text, take a picture, take a video, record audio, grab a screen shot, grab call log, etc. and all those other things that you typically should be able to do with any "Find my Phone" app.
Not sure I'd want to self-destruct automatically though because even I have been known to mess up my password 3x.