React Native building block are its reusable components which compile directly to native components for each platform which gives consistent look and feel. The App will have similar speed and theme which you get on native apps.
Virtual DOM in React Native make developer’s work faster. It updates changes faster without effecting other user interface element. Allowing highly dynamic UI with developer being able to do hot reloading which means they can apply changes in real time mode. Overall a great productivity gain for any app developer.