What is the purpose of having sesame seeds on hamburger buns?

There is no functional purpose for having sesame seeds on hamburger buns. The practice originated as a marketing tactic by the Fleischmann Yeast Company in the early 20th century. The company's yeast was used to make the buns, and they added sesame seeds to make them more visually appealing and unique. Other bakeries quickly copied the idea, and sesame seeds became a common feature of hamburger buns.