Only because you don't have a choice in a kart, left foot brake or crash...!!! :scare:
I hear you, I love to kart, but as soon as I get in a car my left foot only does up and down, no finesse. In a kart it just feels right. I guess for me it's like footy, left foot for standing on, right for skillz. Given some private road and someone else's car, I'm sure it's learnable.