A couple weeks back I was on a panel about "whether social media is good for journalism".
Clearly it is, and these innovative uses of Google+ by journalists are yet another sign of it.
Some use cases I see likely to spring up:
1. Information gathering / story sourcing - We've already seen a few stories sourced from G+. Google is breaking a lot of its company news here (eg. Larry Page posting about their earnings call), while we based a story yesterday on a G+ update about genders on Google+. Media outlets like ours need to follow Google+ closely for the next breaking story, as we do with Twitter.
2. Additional information - Like blog comments, G+ adds additional info to the story that can later be added back into the original article. Articles continue to be a conversation starter for a wider conversation -- they are the beginning, not the end, of the story.
3. Increased reach for stories - Google+ users, like Twitter users, act as editors for groups of friends. Quality stories that appeal to this distributed edit team will carry much further across the web.
4. Listening role - Publishers need to listen to their audiences through platforms like G+ to ensure their content is meeting ever-evolving audience needs. G+ provides a wealth of information about what content is useful to readers and what content is not -- publishers need a feedback loop from G+ straight to their writers.
Any additional use cases you see?