Why don't iPhone users just download google hangouts? Instead of Facetime?

Works just like Facetime but you can video call anyone on any device. And you can have up to 15 people on a video call, and message and screenshare. Facetime can't do any of that. But iPhone users rather everyone buy a iPhone just to facetime when they can use hangouts and video call the same.

Sarcastic reply… Do you know any iPhone users with 15 friends they could Facetime with?

No reason to get BBM or Hangouts, both of which are multi platform chat options, with Hangouts allowing you to use a computer as well as other devices. If you only Facetime with the same 1 person, day in and day out, no reason to have several video chat apps, if the only person you video chat with owns an iPhone.

Because facetime is native to the iPhone. This would be like buying a second car even though the one you already have works just fine.

Because facetime is 10 times better. Thats like saying why use imessage where there are other message apps. There isn't anything as good as imessage.