No, React Native does not compiles JS to native code instead it used native views of the underlying operating system and runs the js code in a separate thread.
React Native is relatively new and it does have platform parity for IOS and android. With just the html and css and little js knowledge you could get an app running of course with degraded performance. Cordova has been around for a long time and it has decent native plugins too.
As the React Native platform matures it will eventually kill those.