1, taste and texture: Knotty lettuce leaves are crunchy and refreshing, and when paired with the burger's patty and other toppings, it can provide a good contrast in taste and enhance the overall flavor experience; romaine lettuce leaves are relatively soft and not as good as the knotty lettuce to provide a noticeable difference in taste in the burger.

2, visual appeal: the spherical appearance of the ball lettuce neat and beautiful, placed in the burger can increase the visual appeal, so that the burger looks more attractive, Romaine lettuce, although the leaves are soft and green, but in the visual effect is not as prominent as the ball lettuce.