I remembered many years ago, all cars have electrical or coolant chokes for carburetors to open up when the weather was cold. We had to wait until the choke fully opened before the car can operate smoothly. Since then, all cars should have electronic fuel injection by now and we should not need warm up the car before driving.
Old habits die hard, and one of the oldest — still rigorously enforced by many drivers — is that “warming up” the car for a few minutes is necessary to avoid some kind of unspecified damage.
But idling is totally unnecessary, which is why many communities have enacted ordinances against the practice.