The spatial element makes total sense. Placement of windows and elements within windows on a desktop computer is really not that different from stacks of papers

The spatial element makes total sense. Placement of windows and elements within windows on a desktop computer is really not that different from stacks of papers arranged on a desk, and spatial memory makes keeping track of it all much more feasible in both situations. It turns your desktop into something resembling a physical space rather than an arbitrary hierarchy. This is actually one of the reasons why I prefer to have a "mess" of freely floating windows of assorted sizes on a 27" or larger screen as opposed to having the same windows all maximized/tiled on a smaller screen. The former of the two setups gives persistent windows a unique place that they "live" on the screen, which makes picking each one out faster for me than if I were e.g. spamming alt-tab or scanning a taskbar to find the window I want.