Honestly, the killer smartwatch feature for me is being able to quickly click a button to find my iPhone. Everything else I use it for feels like I'm just trying to justify spending hundreds of dollars on it. I record all my workouts and my sleep patterns etc., but I never use that data for anything. I wish I could buy a $10 digital watch that also had a "find my iPhone" button.

Casio WSB1000 is probably the cheapest with phone pinging ability, but it's about $40.