He "stumbled" on it from his own experience as a stutterer. Its not necessarily a "cure" but more like steps to take to get to a place where it can be seen as a cure. There is proof of people who are getting better by using his methods. It takes work and motivation. You dont need to compare this with any weird circumstance like driving a car. Try if you want to try, or dont. I get why you are aprehensive about it though, its totally understandable. In this case, its not necessary to be so dismissive. Have an open mind.