I don't want to play the guessing game of "does setting the temperature at 68 mean I'll get cold or lukewarm air right now?" All I'm left with is a choice between full cold (60F) and full hot (90F) if I'm not in the mood for the computer's guessing games. When I want cold air, I want cold air. When I want lukewarm air, I want lukewarm air. When I have to pick a set point, I get air that isn't right half the time its running. What's worse is that many systems, like that on my Nissan Altima, will override the A/C selector switch. That means I can't help but run the A/C compressor, wasting gas, when I could just be drawing in outside air when the temperature is just fine.
Radios have been terrible for a long time now but the shift to user-unfriendly HVAC controls is the last straw for me.