This isn't really accurate. Presuming you're using react-native-web [1] (the most popular version of RN targeting the web, although there are others), it's essentially just a set of components and APIs, fulfilling RN's API, which sit on top of React DOM.
So anything you could do in React, you can also do in RNWeb, as it's a superset of React.
Of course, you'd need to use the RN components if you want to share code between web and native mobile. But there's nothing stopping you reaching a high degree of code re-use, and/or using React components for the web-only portion of a RNWeb project.
So anything you could do in React, you can also do in RNWeb, as it's a superset of React.
Of course, you'd need to use the RN components if you want to share code between web and native mobile. But there's nothing stopping you reaching a high degree of code re-use, and/or using React components for the web-only portion of a RNWeb project.
[1] https://github.com/necolas/react-native-web