He did it for fun. From the Github: > Finally, a "back to top" button that behaves like a real elevator, by adding elevator music to quietly soothe the awkward

He did it for fun. From the Github: > Finally, a "back to top" button that behaves like a real elevator, by adding elevator music to quietly soothe the awkwardness that can ensue when being smoothly scrolled to the top of the screen. This is very serious stuff, here's a demo!