When ESNext (i.e. ES6+) files are used natively, you gain these benefits: It is much easier for debugging as your are debugging your source code, not compiled code Can be faster due to: Polyfills having to work around native features by going the long way, which can be very slow (e.g. () => {} vs function () {}.bind(this) JavaScript engines are better able to optimise your code due to the source c