The Classic Mac Finder was designed to look like a desktop (The desktop metaphor).
What used to be called GUIs (graphical User Interfaces) have a 'spatial' element - If you want to put a file in a folder - you drag the file onto the folder.
Apple used to call this principle 'Direct Manipulation'
Direct manipulation allows people to feel that they are directly controlling the objects represented by the computer. According to the principle of direct manipulation, an object on the screen remains visible while a user performs physical actions on the object. When the user performs operations on the object, the impact of those operations on the object is immediately visible. For example, a user can move a file by dragging an icon that represents it from one location to another or can position a cursor in a text field by directly clicking the location where the cursor should be placed.