In XF1 I made a simple add-on so I could add Adsense with custom phrases to different templates. I just wanted to make it easier to manage the phrases as a whole in the event of upgrading, etc. I upgraded the add-on to work with XF2, but I like the Advertisements system better because it will not show ads on templates for you automatically. If there was a way to export advertisements from my test install, then I could quickly re-import them after upgrading to XF2.
This might be a use-case that's really only useful for me, though.