I’m very involved in this space. The company I work for wrote a library similar to Next.js before it was announced and before create-react-app. There are so many things that these solutions solve to only focus on SSR is missing the point. SSR is one benefit of many and others have already explained why they care about that. There are many use cases where both SEO and complex interactions make sense on the same page. Next.js is also going to help you with overall architecture decisions like routing, page level code splitting, where you fetch data just off the top of my head. Sure you can build these yourself, that’s what I did before Next.js was a thing but now that I have a deep understanding of all of the things we wrote. I would use an existing community backed solution before building from scratch in a new app. We are even very interested in migrating from our home rolled solution. Currently we are vendor locked into our own creation which means we have to continue to maintain it. It is way more expensive than any lock in that would have come with Next.js.