Earlier quoted context omitted.
Some would say having your family members avoid G+ is one of the primary benefits of G+. So instead of being barraged by a stream of photos of cousins and aunts you haven't seen in decades, or discussing family gossip, you get to engage in interesting conversations based on people with similar strong interests in particular topics. None of the people I follow on G+ are 'friends' with the exception of co-workers, inst…
That doesn't sound like a very good "primary benefit" since Google's strategy is clearly to get as many people to use G+ as possible. Either a) they'll be successful and your G+ stream will be barraged by "photos of cousins and aunts" anyway or b) it's not successful and they pull the plug.
Having a segmented by interest social network is a primary benefit. I come to HackerNews not because I'm friends with anyone here, but because I can interact with interesting people here. It's also why I go to G+ every. The level of dialogue on G+ is much better than Facebook on average, and the G+ communities are a lot better than Facebook pages.