1) React/jsx is legitimately nice for templating. Lets say I have a list of ten things I need to display; I know these things at build-time, its not dynamic like from an API or whatever. These ten things are reasonably complex; div+spans+borders+etc. React is all about components; it makes that easy, write once and copy-paste one line. There are ways to get similar behavior in plain HTML+CSS, but it tends to be leveraging web technologies that I'm not super familiar with (web components?).
2) React has an EXTREMELY good developer community. Everything you could possibly want, there's a component out there, and its an npm i away. In comparison, the more pure HTML/CSS world is more fragmented and less developed.
3) `next export`. When people think nextjs, they think SSR. Don't bother with it. Just `next export`. I leverage next for the local dev tooling, the runtime can take care of itself.
4) Or; I want server-side functionality. You can build backend-only API routes, in Next, and its actually awesome. Of course, you have to give up the static export, but its the first full stack JS "framework" where I've started thinking, this actually works & feels productive. Usually I leverage that for really simple stuff; server-side OAuth logins for hacky dashboards, things like that.
For deployment: netlify is nice, or I'll use digitalocean apps if its not a static export.