There's another angle: system independence. When things go wrong, i.e in a crash, you still want to guarantee an undammaged door latching mechanism can still b

There's another angle: system independence. When things go wrong, i.e in a crash, you still want to guarantee an undammaged door latching mechanism can still be operated independent of other parts of the car being damaged (likely). To satisfy this for a purely electrically actuated latch you would need a battery and independent controller in every door. It's hard to beat the reliability of a mechanical latch and a human hand to satisfy that requirement.