The way I see it.. is you don't necessarily remember where you left them.
If you start moving and the wheels are turned.. and someone is standing close to the car.. "Ooops..sorry about your toes..hope they grow back."
If you have an emergency and jump in and try to take off quick.. near a building or something ..you could hit it...
And in the case where I am helping my mechanic buddy... you are always jumping in a customers car for a brief time. No need to adjust the seat or mirrors.. and when they get in..you want them heading straight..