From the blog post "Disclaimer: I still haven't tried Hangout, not enough people in my circles yet."

I don't think Google Hangout will have the same use case as most Skype video calls/chats (which are a one to one communication, or at least I would assume).

I think if anything (and this may be OT), companies like Path and the numerous group messaging apps should be the ones concerned with Circles and Huddle respectively.