It's less about code reuse across a full featured web application and a mobile application. The value comes in that once you master React or React Native, you can easily switch across platforms and be just as efficient. If you learn the ins and outs of Vue and gain depth of best practices / domain knowledge, you are stuck building only for the web.

If you do the same with React, you are then able to take those skills and build VR, Web, iOS, Android, Windows, and soon TVOS ++ many more in the future.

This, along with what has already been stated, is the value of using React vs Vue imo.