Okay.heat transfer is improved. you get better heat transfer to the heater core and to the radiator, lowering your coolant temperature and increasing heat to the cabin. when the engine is cold (less than 180f) the thermostat will be closed so no heat will be lost through the radiator.
tldr: since heat can transfer from the engine to the radiator/heater core faster, you get more heat to the cabin/atmosphere and less heat stays in the engine
I did get good grades in thermodynamics in college, but I’m still a little lost here.