The only real advantage that I see is that this somewhat explicitly states that `settings_base.py` is meant to be the **base** settings for the project.  Someone stumbling across the project might overlook the various different `settings_*.py` files.  By having all of the settings in 'settings_base.py' and having 'settings.py' file be a barebones file, it seems a bit clearer that there is some form of evil wizardy at work.

I'm not actually convinced this is a good idea, but above is the best case I can make for this setup.  So, +1, meh, -1?