You can make it zero-config, polyfill everything, apply all babel plugins so everything is transpiled to support IE 7, for all you care. But everyone has diffe

You can make it zero-config, polyfill everything, apply all babel plugins so everything is transpiled to support IE 7, for all you care. But everyone has different needs. So tools like Babel and Webpack allow you to pick-and-choose what polyfills and transpilations are necessary.