It still requires you to setup an XMPP server and proper DNS for federation.
With hangouts, if someone has a google account, there isn't much else to setup which makes things much easier for non-technical friends & family.
Hangouts has other benefits:
- All users support the same call/video features
- Using GCM means that battery life is better than with long polling, in my experience
- Integration with Google Voice means you can add phone users to your video call
- Sending images is built in
- Single chat history that's synchronized[1]
- Works on Linux, Windows, macOS, Android and IOS with the standard clients[2]
I've setup an XMPP server before and it wasn't that hard. I have friends/family using Hangouts and Signal messenger. Hangouts provides a pretty smooth experience and is my generally preferred way to initiate a video call with my family who runs a variety of platforms (Andriod, iOS, Windows, macOS, etc)
[1] Of course this is possible because of Google being the hub with is the grandparent's concern
[2] XMPP also has this but some chat solutions are not as widely available. Of course the web app will work anywhere you can run a modern browser. I'm thinking of the official Chrome extension and I don't know if it works in BSD or other OS's.