It is probably a good idea to have a goal in mind when learning things, but many of these are not the usual goal for the subject matter. For example, most people learn statistics to fool themselves and others. His suggested goal is better, but it is important to know that it is different, which is a detail he fails to mention. In some of these cases, if you just keep your eye on your own purpose while following usual routes, it will work, but in other cases, you should probably look for other routes.