React is a decent framework conceptually and more importantly it has become a defacto standard for UI development in JS. On top of that the sheer amount of React support in terms of components, tooling and learning resources is immense.
NextJS says “use what you already know and use on the backend (React), and not only that we will make it seemless to use the exact same code to render an initial paint for time to render/seo as you do for live updates, and we will chuck in static site generation for free”.
Tailwind is another thing that seems really really odd, until you use it and then it seems brilliant. In a nutshell it is css classes like “m-1” for a small margin.
It would be awful for a handcrafted static site, but it works great with React because it plays well with componentizing code. If skeptical read their site where they address the obvious reasons for being skeptical.