Story-driven effects
Anytime Vision is actual Vision, that’s an effect. In reality, Bettany is painted purple and his finished look is added on later. Since that’s expensive, the producers would always discussed how often he needed to be in that form. The answer was when the story dictated it. So, when Vision is home, he’s comfortable, and he’s his true self. (Side note: in the black and white episodes, the purple didn’t work for effects so they had to paint him blue.)
