Do not forget React is not equivalent to an SPA. Almost all SPAs give the entire body over to React but its also possible to choose a smaller DOM node and add

Do not forget React is not equivalent to an SPA. Almost all SPAs give the entire body over to React but its also possible to choose a smaller DOM node and add React progressively to any existing website view that would benefit from the React paradigm. In this setup (at least) server-side rendering is no longer needed and thus simplifies setting up the build process. So its not all or nothing, you can pick and choose where to use React based on your needs and requirements.