That’s absurd, that’s like saying we should only use C++ for backend code because my CRUD business app might one day scale to infinity. Better be safe than sorry and sling pointers and CMake just in case I need that extra juice!
Not really. If you use react router, you can have a client side js app and add SSR with a couple of hours work. You have your cake and eat it
imo, even if the only "interactivity" a web app has is just a login page, then even that alone is enough to warrant using a framework rather than doing direct DOM manipulation (or even worse, full page refreshes after a form submit).
It's not about using the most powerful tool always, it's about knowing how to leverage modern standards rather than reinventing and solving problems that are already solved.