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.
But you already agree you can USE left foot braking with finesse, just transfer that learning to your car, if your choice was crashing
in your car or using your redundant left foot to hit the brakes ask your subsconscious what it would do..! :surrender: