Arguably, using React where a static HTML with maybe a little bit of vanilla JS would do, is code golf.

HTML and CSS are not bytecode. They're high-level abstractions, hiding a very complex renderer underneath. Sometimes you need to build another tower of abstractions when this doesn't suffice - like when you're trying to build an application with complex GUI in the browser and you need an adapter between DOM and a more suitable GUI pattern. But displaying text and images communicating a message is not one of those cases.