This is undeniably neat but I am curious if you "know what to do" because you have a lot of experience using applications that looked this way largely by necessity. I don't think the average computer user would favor this type of aesthetic on any level.

When I was growing up with computers, interfaces like this were on their way out. So to me it just looks clunky and messy. Other than inspiring nostalgia and impressing me with the amount of work that surely went into creating it, I don't think this theme has much real world application.

These themes that attempt to replicate the look and feel of a GUI are pretty gimmicky in nature (ever been to a terrible blog that tries to look like the OS X GUI or worse... one of the Windows GUIs?). This one just happens to be really high quality.