How often you find yourself locked out of your house obeys Murphy's Law, add lots of security and you will find yourself annoyingly locked out for silly reasons all the time. Have just the one simple lock on the door and you probably will not end up locked out, particularly given there is a key under the mat.

I had a laptop of mine retrieved by the police from a big rubbish bin. The screen was broken, it did boot up though. Another time I had the broken screen after being hit by a car. These things happen and I am always sure I can get in even if keyboard/screen/mouse isn't an option. It is more useful for me to be able to somehow access my machine even if broken, I imagine there will be circumstances of that.

When the police retrieved my laptop I wasn't exactly worried about my obvious login password or whether I had locked down that mysql port sufficiently. The thief wasn't even literate so those extreme security measures wouldn't have helped.