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.
> ...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
Maybe, but it doesn't necessarily need to be a SPA framework though. There are simpler libraries/frameworks like htmx that considerably reduce complexity and also let you avoid direct DOM manipulation.