But when it comes to self defense I feel its better to be better trained than one needs than to need to be better trained and not have it. So my advice is to train all one can.
As to this line in your post "if you look at the odds your money would be far better spent on advanced first aid training or defensive driving skills, even better nutrition. " My next class the last weekend of this month is TRAUMA MEDICINE FOR THE CCW OPERATOR and I'm working on a better nutrition diet and losing some weight.
So which of this thing you mention are you working on? Or do you have it all under control and there is no need for anything new?