Am I the only one who still uses hangouts? For some reason its the app my wife and I use, i dont use it with anyone else. It's handy that it pops up in chrome, and my Google Fi messages pop up in it too.
I still use it because it's available on Windows, MacOS, and Linux as well as both Android and iOS devices. My friends and family are on a variety of platforms but we can all use Hangouts. I still dislike some of the changes they've made as it moved from the old Google Talk to Hangouts but being able to follow conversations on mobile and in my browser is great.
I have a few friends who use iPhones and occasionally complain because they want to use iMessage, but a good 30-40% of us can't run it since we don't own iPhones or Apple computers.
It's a great solution, and it'll be a shame if Google ever really gets rid of it.