What are the best uses for the Django Admin app?
Some of the uses I can think of - 

Editing data or Adding data. If you have any sort of data entry tasks, the admin app handles it like a breeze. Django’s admin especially shines when non-technical users need to be able to enter data.
If you have understood above point, then this makes it possible for programmers to work along with designers and content producers!
Permissions - An admin interface can be used to give permissions, create groups with similar permissions, make more than one administrators etc. (i.e. if you have a login kinda site).
Inspecting data models - when I have defined a new model, I call it up in the admin and enter some dummy data.
Managing acquired data - basically what a moderator does in case of auto-generated content sites.
Block out buggy features - Also if you tweak it a little, you can create an interface wherein say some new feature you coded is buggy. You could disable it from admin interface.

Think of the power this gives in a big organization where everyone need not know programming.
On the website, it says this: 

One of the most powerful parts of
  Django is the automatic admin
  interface. It reads metadata in your
  model to provide a powerful and
  production-ready interface that
  content producers can immediately use
  to start adding content to the site.
  In this document, we discuss how to
  activate, use and customize Django’s
  admin interface.admin interface.

So what? I still don't understand what the Admin interface is used for.  Is it like a PHPMYADMIN? Why would I ever need this?