JavaScript frameworks don’t exist to provide user demanded features but to provide developer demanded capabilities. Since frameworks exist solely to supplement the developer no site really needs a framework and sites benefit universally from not having one.
I used to have a JS-free site, and even though it had background animations, they could all be done with clever CSS. Unfortunately I wanted these animations to persist as the user clicked around the site, so that they could grow in complexity or interesting-ness over time, instead of resetting. This is not possible without a JS framework to turn the site into an SPA, so I switched the other way, from eleventy to gastby.