If show covering the camera lens is an issue, why don't you clear the snow off the lens? Don't you clear the snow from your windows before you drive? Why wouldn't you do the same for the camera lens?
When starting out, cleaning the lens off is easy, but when you get to your destination, it’s not that easy, especially in a crowded parking lot. You could clear the lens off when you leave, but the snow/rain that’s being sucked into the rear of the car will still cloud the lens by the time you get there.