Imagine. You open an IDE. You see a list of projects. ZOOM into the project you want to work on. You see a list of packages. ZOOM into the package. You see a list of classes. ZOOM into the class. You see a list of variables and methods. You can move the methods up and down, etc. ZOOM into the method and you can edit the code. ZOOM into the code and you can see e.g. call diagrams or documentation. What do you think?
The point is you can zoom in and out easily and quickly navigate on various levels of abstraction.
