I just finished a simple "daily reminders" app for a client (using React Native). It's a huge winner for small apps like this. I finished in mere hours with zero iOS or Android experience, but I'm on the fence about whether it's useful for much else. Facebook and Airbnb have the money to absorb its idiosyncrasies, but startups and the app middle class possibly don't.
Whatever camp you may be in, how are you using React Native and how is it going?