I don't get the watch-craze at all, as it adds 0 things you couldn't do before. However, i m looking forward to Android Auto, something that i wanted for a long time.
That's your opinion. For me it has been life-changing.
Besides that, I mainly use it for "watch" stuff.
That said, it is really nice to be able to get notifications without taking my phone out in certain contexts—bicycling, walking, in a pool, phone charging in other room, etc.