With Webpack and CommonJS, the way you register directives, services, etc. with your modules can be a lot more modular. See how to register a directive with an Angular module using Webpack.
Intro to Webpack
Angular with Webpack - Production Source Maps
When you uglify your Angular code with Webpack's uglify plugin, debugging your application can be a nightmare. See how easy it is to add source maps to your bundle so you can easily debug even in production.