In my opinion, whether C1 or C3 should be guided by what you feel most comfortable/safest with. If someone is a sleepwalker, they shouldn't keep a gun with a round chambered for obvious reasons. If one isn't, that's different.
There's a scenario which is not all that far fetched, IMHO.
Some monster has broken into your home, and is in your bedroom, in the dark. If you don't have a round already chambered, how quietly can you rack the slide and get ready? I can tell you I can't rack a slide with no sound; perhaps you can. At that moment, if you are laying in bed and can slip your hand onto a ready to fire handgun, you have the best chance.
Some burglars/rapists/murderers/etc. can get into unlikely places pretty quietly. As for me, I want to be ready to rumble if that fateful time comes.