I think there’s no binary answer to whether or not React Native is a viable option. I can definitely imagine a bunch of situations where that would not be the case, but in our case the app is largely just a collection of views that show remote JSON data. Some small animations are done using the React Native animations API, but e.g. our navigation completely relies on native APIs and also has custom native transitions.
In short, I think that the companies that will succeed with RN are those that have native experience and a can-do-self attitude, both to ensure proper platform UX and deal with lower-level details such as RN bugs and limitations that would prohibit the product design from being possible to implement at all (for instance, in our case nested scrollviews); or those that are willing to sacrifice on UX and product design. (Not making any judgements here btw.)
We’ve written a bunch about our experiences https://artsy.github.io/series/react-native-at-artsy/ and I recently spoke about our specific case of integrating RN into our existing native app at React Native EU https://github.com/alloy/react-native-eu.