Currently, yew.rs is built using Docusaurus, which uses React. It was used because at the time Yew did not have a way to render page to HTML files (SSG). This has now been resolved for the most part.

https://yew.rs should be built using Yew. It would be better to build a documentation engine like Docusaurus, then use it to build the website. But that's a huge undertaking that I'm not sure if anyone is willing to take on right now