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, instead, they are people who have very interesting things to say and who I like interacting with. Twitter would be a comparable use case, but it is too annoying to have long form stream discussions with followers like this.

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.

I don't think it's either-or. Even if they show up, G+ is by default, an asymmetric model. And G+ isn't just about the "stream". Google would have done something like G+ anyway to unify 40+ services. You might be right that they want more than a niche audience, on the other hand, Google does want to elevate the public square.

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.

I feel similarly. What I've been doing is just deleting my G+ account each time Google creates it, but if it becomes too much of an issue, I will be forced to switch. A real pity - I love gmail.