This is not a webdev stack. It is build tools. you do not ship them to your users (like react/vue) but are you used by developers for local build and CI servers for prod build.

As for why? some people have very large codebase and prefers their developers to have better UX and are willing to pay for it. lower CI/CD server costs also directly translate to cost savings if you are Replit or stackblitz,

You may not like it, and that is ok. as individual developers are already benefitting from vite. and will get rolldown soon.