It gives a read-only peek at the scope of the imported module.<p><pre><code>    import {foo} from &#x27;bar.js&#x27;;
    &#x2F;&#x2F; you can&#x27;t re-bind `foo` from here, but if
    &#x2F;&#x2F; a function defined in &#x27;bar.js&#x27; mutates it, 
    &#x2F;&#x2F; the change is reflected here too.
</code></pre>
It enables circular dependencies, for free, and makes it easy to discard unused code.<p>See the examples at the Rollup playground.<p><a href="http:&#x2F;&#x2F;rollupjs.org" rel="nofollow">http:&#x2F;&#x2F;rollupjs.org</a>