My daughter uses facetime every evening talking to one or another of her girlfriends from high school. I think certain demographics will be more inclined to use it than others.
So in essence this is an attempt to be a facetime competitor?
Facetime/Facebook video chat/et. al. Granted it has some limitations that would prevent it from, at least initially, being a full competitor. I suspect that over time Google will flesh out it's features with either a web version, or dedicated apps for other platforms. Right now I think they are at the minimal viable product stage.