There's a lot to be taken from Walt's speech about his father. It explains so much of why he is the way he is now. His constant worrying about how he may be perceived as weak by other people, specifically. His character traits are most justifiable and possibly even sympathetic as a result of knowing some of his history.
Also, the payoff with Walt, Jr. pointing out how differently Walt has been since he started cooking came as a surprise to him. This is consequential stuff in how Walt operates moving forward. It's a necessary aspect of the show.