Unfortunately, at least here it is the case that it also involves cold wet weather. For me, the effort would be too great, sometimes ventilating, sometimes not... Should one then open/close the ventilation openings depending on the weather? That would be too much work for me to change 100 times a year. I don't even drive a diesel, but if you don't have stop-and-go city traffic right in front of the house, a car in winter doesn't really get hot. Apart from a few engine parts, there's not much warm mass in there. The best test is to sit in the car without the engine/heater for a few minutes in winter to see how quickly it cools down.
from the road Edit. A four-cylinder is nowadays no longer a small engine at all, small are the three-cylinders, which already have over 100 hp, which is more than suitable for everyday use.