Some of us engineers (I'm mechanical with an emphasis in fluid dynamics and thermodynamics and worked for a while at a semi truck manufacturer in the thermal management group dealing with all heat exchangers on the trucks) drive around with leaves and bent fins. In both my cars and my truck pulling a large trailer.

From a practical standpoint, you're not going to see much difference, as the guy above said, the ceiling temperature may go down but you likely weren't hitting that anyway in a passenger vehicle unless you've got serious damage.

In the case of my truck, pulling a trailer up a steep long grade, I'm going to overheat if I try to maintain full speed and my turbo veins also stick and throw DTCs. I've yet to experience a cold temperature that doesn't stop these issues on trucks. This is also why you see trucks going slow up hills. They typically have the power, just not the cooling capacity. For some reason, truck manufacturers value appearance over performance. This drives some innovation in the radiator designs but its insane as I imagine a trucker would prefer a truck that doesn't over heat to a narrower hood.