Why do commercial flights and training flights need to be mutually exclusive? When you go to the hospital, the doctors who see you may well be in training. Even after training, as consultant or attending physicians, don't you agree that they're honing their skills with each new patient?
Nobody's suggesting we go around pulling breaker to see what happens. I don't even consider flying around with 0 automation to be training, really- it's more about maintaining a firm grasp on an ablatable skill set- one which we may need to call upon without as much as a moment's notice.