Since GNOME 3.6, there is now support for offline updates. Updates are downloaded silently in the background and installed while the system isn't running.

However, if updates are available, you still get a "Updates Available" notification. If you click on it, Software Updates is launched and the updates are installed in the old way (they are downloaded in front of you, and then they're installed while the system is running).

Issues with this:

 1. Making the user wait for updates to be downloaded isn't a good experience.
 2. You expose the user to all the problems associated with installing updates while the system is running.
 3. It leaves two models for installing updates - online and offline. This is confusing for the user - which is the right way to install updates?

A suggestion for what to do instead:

 * Always download updates in the background.
 * When the updates have been downloaded, show a notification ("Updates Ready") with a button "Show Updates".
 * Clicking on the notification or the Show Updates button launches Software Updates, which has an Install Updates & Restart button.