Hangouts is designed for a specific purpose, telepresence meetings, and it does that well. It's not set up for the use case that WebEx and GlobalMeet and others serve. For example, when I join a hangout, I get a video chat. That's almost never what I want for work. I want a system where the meeting leader can join ahead of time, set up slides for presentation, have a list of attendees and be able to mute and message them, set up polls if needed, be able to connect audio-only participants via a dial-in number, etc. Most of those individual things can be done with Hangouts (no dial-in numbers, though, which is critical), but the workflow isn't set up that way. It's not a product for business.
If you follow the link I sent above, if you have GAfB the individual users have no way to disable auto-hangouts, for their comfort and safety. It has to be done at a domain administrator level.