G'day, sorry to hear of the devastating results you had with your car cover.
Living in Australia means we don't have the cold climate extreme you have there and virtually no-one here uses car covers in open areas or carports for climate protection (even though we can get pretty hot summers). I thought of using a car cover once but not after seeing the damage done to a friend's car.
His experience using a car cover (outside) resulted in the chrome work on his classic car including the door handles, chrome strips etc. pitting badly and also allowed rust to invade many areas, mainly around the windscreens because the car cover held the moisture inside and had no ventilation at all.
It was a good quality vinyl coated car cover with a kind of flock (cotton) interior covering and had an elasticised base to keep it in place.
In my humble opinion, car covers should only be used when a car is put in dry storage in a garage or shed (mainly to keep any animals droppings off it).
Also when used outside, the wind can rub the car cover over the paintwork causing scuffing and marking unless it has been firmly tied down. I would never use a car cover for any purpose after seeing first hand, the damage done to my friend's classic car.
JR