On the ground your floor is either a basement or well, the ground. Whereas on higher floors your floor is another apartment and your roof (might) be the actual buildings roof.
Heat leaves far more easily if there is air on the other side of the wall and(!) you have the benefit of ground isolating you on the bottom floor
I was clearly implying that there has to be another apartment on top of yours (so, a 3 floors building). If you compare ground floor vs top floor, then ground floor wins hands on, I agree.
Heat leaves far more easily if there is air on the other side of the wall and(!) you have the benefit of ground isolating you on the bottom floor