Comment 6 for bug 689523

The usability problem is not the fact that an unused package is left on your computer taking up space, it is the fact that two dead menu entries are created.

Imagine an "average user" browsing through the software center sees Evolution and thinks "Hey, I use Gmail and never use that program. Ill uninstall it." Later they are finding a program in their 'Office' applications and see Evolution listed. This creates confusion. An average user might think to themselves, "why is that still there? Maybe I have to delete items manually?" There is also an item left in the system preferences menu titled "Email settings" which is specific to Evolution. Clicking either of these brings up the error message:

Could not launch 'Evolution'
Failed to execute child process "evolution" (No such file or directory)

The point is that this bug creates confusion and unnecessarily cluttered menus. I am no expert but it seems that it should be relatively easy to fix. Uninstalling evolution-common removes both the dead menu items, so the fix would be adding evolution-common to the list of packages removed when you uninstall Evolution from the software center.