Your friend is on the right track. The Fahrenheit system has a smaller unit degree than Celsius/Kelvin (1 degree C = 1.8 degrees F), which gives it more precision when discussing temperatures in casual conversation. It also helps that the range 0 to 100 F corresponds roughly to the usual range of temperatures that humans tend to experience. It's a nice, round range, and it's easy to identify "below zero" or "above 100" as relatively extreme.

As a physicist, I do almost all calculations using the SI/metric system, but I have little intuition for those units in everyday life. Much of that is, I'm sure, having been raised to use imperial units, but they do tend to be better adapted to usual human scales.