Keep in mind that McDonald's is an established brand. They don't have to explain what "McDonald's" is anymore -- they're past that point. Now, they have to convince you to eat there by associating themselves with health-conscious imagery and family-oriented messaging.

This is an attempt to make McDonald's seem more "fun" than the average restaurant.

Most companies looking to build a web site are trying to solve a totally different problem because most companies are still trying to explain who they are. You definitely don't need a physics engine to explain who you are.