Another benefit of using a framework (especially a popular one) is it makes hiring / onboarding easier - a lot of candidates will already have experience with React / Vue / Angular.
Yes, as long as you are willing to establish your own "framework" if you need to collaborate with others. I've personally found the trickiest part is keeping common HTML fragments and CSS standardized across the site. If you can get it down to a common Layout.html, Navigation.html and Site.css, you will probably be able to manage the complexity in a reasonably-sized team. If you need to edit one of these common files, convene a meeting. Everything else is an independent partial with its own HTML/CSS/JS.
The hardest part is learning how to do everything in direct terms. MDN is your bible for this mission.
If you are building a website, then you probably don’t need one.
MV* is a good way to organize projects for teams. If you're doing a blog, personal site, or other project you don't expect to grow into something contributed to by multiple teams, the value proposition is different. Not saying frameworks or MVC are bad in that case, but they can become just another thing to worry about for a solo dev.