what's so wrong about playing on auto-pilot?

i just read a post about theory vs. practice and there seems to be a notion that playing on autopilot is a negative. What is exactly wrong with this? If you know all the angles and have played each situation so many times, you can play on autopilot. In a way, you don't have to overthink each play, making the right instinctual play because it just feels "right". Or is this not what playing on auto pilot is?