They have to cover all the bases. Phantoms - and quadcopters in general - are only some of the sUAVs out there. Fixed wing aircraft are a different beast, and have different implications with temperature on their lift and control surfaces than rotary wing. Some people live close to airports and some more than others will have a greater need to understand how to determine where the different classes of airspace are. Here in Florida, you can't throw a rock without hitting an airport, heliport, or seaplane base, so there's lots of Class D and higher airspace to be aware of. One of the places I want to fly one day is a marina lined up perfectly with a small nearby airport's runway, so being able to look up the CTAF frequency and listen for aircraft coming in to land or takeoff would be important. Am I worried about frost? No. But that doesn't mean that the information is not useful.
I agree and appreciate everything you said except "Fixed wing aircraft are a different beast, and have different implications with temperature on their lift and control surfaces than rotary wing"
While rotor craft are a different beast they are not immune to physics. Temperature affects Density Altitude (DA) so it effects lift of a rotor wing just like it does a fixed wing... Ask any Helicopter pilot.
While on the subject of DA it will also affect the cooling of our little electric motors. The higher the DA the hotter they run.