title: Is it better to have polyfills as import statements with babel-preset-env or add them in entries at webpack.config.js?
body: <p><code>babel-preset-env</code> offers the option <a href="https://github.com/babel/babel-preset-env#usebuiltins" rel="noreferrer"><code>useBuiltIns</code></a> to apply it to <code>babel-polyfill</code> and transform <code>import 'babel-polyfill'</code> to specific, environment-based, <code>import 'core-js/whatever</code>.</p>
  
  <p>Is this transformation applied if I add <code>babel-polyfill</code> in my Webpack entry section (see example below), or in that case <code>useBuiltIns</code> is ignored and replaced by all possible imports?</p>
  
  <pre><code>entry: {
    app: ['babel-polyfill', './src/app.js']
  }
  </code></pre>