Why does selfie shot save mirrored images?

I can't think of a single reason why it would do this, but it does. Why would I want everything inverted in the saved file?

I know it's wrong because I took a photo in a car and now I'm sitting on the wrong side of the car!

Worse, it saves it backwards with no way to undo it.

Yes, I know I can fix it in third-party software, but I have absolutely no use for the camera to save trashed photos like these.