React and similar frameworks excel at interactive interfaces and design systems at scale. For a straightforward marketing site with a blog, WordPress or another CMS often ships faster and empowers non-developers to publish.
Consider React when you are integrating with a larger product ecosystem, need advanced personalization, or have engineering resources to own deployment and content workflows (possibly headless).
Total cost includes not only build but also who will update the site in six months. Pick the stack your team can sustain.