The pink elephant in the room is that, because of how JavaScript is delivered to the world, we cannot just start using the latest ES2017 features. In frontend JavaScript, we are limited by the fact that old browsers are still in use. Internet Explorer version 6 has fortunately been almost completely retired, but there are still plenty of old browsers installed on older computers that are still serving a valid role for their owners. Old browsers mean old JavaScript implementations, and if we want our code to work, we need it to be compatible with old browsers.

Using code rewriting tools such as Babel, some of the new features can be retrofitted to function on some of the older browsers. Frontend JavaScript programmers can adopt (some of) the new features at the cost of a more complex build toolchain, and the risk of bugs introduced by the code rewriting process. Some may wish to do that, while others will prefer to wait a while.

The Node.js world doesn't have this problem. Node.js has rapidly adopted ES2015/2016/2017 features as quickly as they were implemented in the V8 engine. With Node.js 8, we can now use async functions as a native feature, and most of the ES2015/2016 features became available with Node.js version 6. The new module format is now supported in Node.js version 10.

In other words, while frontend JavaScript programmers can argue that they must wait a couple of years before adopting ES2015/2016/2017 features, Node.js programmers have no need to wait. We can simply use the new features without needing any code rewriting tools.