The same process could be employed by any high-profile twitter user to take advantages of some unique +Google+ features.
Let's dive in ...
For reference +Elon Musk tweets here.
Like many high profile social media users Elon has chosen Twitter as his social media vehicle of choice, seems to like Twitter and occasionally replies to other users!
Google shows three social profiles for +Elon Musk in the knowledge panel: Twitter, Instagram and Google+.
Elon does not currently use his verified Google+ profile and ...
... I would not suggest that he should. At least not like a "normal" user. Like me.
Using +Google+ can be time consuming because it is (don't smirk) a very social platform. If you are well known it's probably too social. Too much effort.
Unlike twitter Google+ has comments. There is a strict hierarchy between the post and comment objects: a post you make, and the comments that other users leave on your post. Twitter's lack of hierarchy means there is not one conversation. Not one post with hundreds of comments like there is on Google+. Instead there can be many "replies" but, most can be ignored. Replies are individual not inclusive.
Some celebrities like +Daniel Radcliffe who famously only uses Google+, have done just that.
Some media brands, like +Top Gear, have also taken the binary path and turned commenting off completely on their public posts (though for commercial brands I don't personally understand why).
Anyway there is another, more interesting, option. Which is to allow only the right people to comment.
Elon (or any high profile user) could allow only some people to comment by setting up a circle, calling it "Can Comment" or something similar and changing their "who can comment on public posts" setting to include only people in the "Can Comment" circle.
Anyone added to that circle could comment on Elon's public posts. Everyone else would not be able to.
From a public relations perspective this would give Elon the ability to have publicly visible dialogue on his public posts, but only with people he allowed. Avoiding the social media "noise" that comes with being someone with whom every tom, dick and harry wants to chat.
Using Google+ with Twitter?
Shares of Google+ posts to Twitter used to look like this. Awful.
That has since been fixed. Shares of Google+ image posts now show a clickable pretty Twitter card which links to the Google+ post.
Google+ excels at long form posts. Look for example at +David Amerland's Sunday Reads or posts by Google's Privacy lead +Yonatan Zunger, which are mostly information rich long form posts.
Elon's comment restricted public posts would not be "comment heavy" like +David or +Yonatan's.
Elon's Google+ posts would be widely shared and hugely liked posts, with thoughtful exchanges between him and those he had given commenting privileges to. Thought leaders, media celebrities, politicians, trusted journalists.
I personally use Twitter and Google+ together, but not set up like this. I do not need to.
If I were +Elon Musk I might not need to either .... but doing so could be interesting.
p.s. Elon feel free to comment privately if you'd like. Or publicly, I don't mind either way 😜