CSS-in-JS originates from the needs for reusable and/or separated web components, so if your website can be factored like them it might be better. To be sure, I do hate "do it in JS" movements and I will gladly get rid of them if I can achieve the same without JS, but it is way better than keeping your HTML (templates included) and CSS (Sass included) in sync. Tailwind does nothing in comparison; it is just an abbreviated inline CSS with opinionated defaults.