Whether you work on one Drupal site or multiple, it is often necessary for your local dev environment to be slightly different from your site's server.  Perhaps you need to disable Secure Pages because you don't want to set up SSL on your local environment, or there are modules specific to your website's server config.  If you work on multiple sites in a sporadic fashion its possible you need to synchronize your local database with the dev server between tasks, that way you aren't missing any updated configurations.

Sure, you can pull this off manually by grabbing the database, reloading your local, and updating your Drupal site's config; but why not add a little automation to help out?