Because we can
Storage space and computing power are dirt cheap; our task isn’t to “use them efficiently,” it’s to “squander them creatively.”
Forget the Files and the Folders: Let Your Screen Reflect Life, David Gelernter.
Or I could tell you about the time Apple released an unbelievably cool, unbelievably wasteful, 3d-rotating user-switching. The best description I read, and it still reads on the feature page: “Because we can.”