[asolove]

This is all true. But people might be more convinced by the bigger reason: developer productivity.

The module pattern boils down to trying to bring the ideas of privacy from Java into JavaScript. Java has good tools (IDEs) for interacting with, debugging, and testing objects with private data and methods. JavaScript does not.

Once you build your encapsulated module, you find yourself adding extra getters and setters to provide visibility to the code you're writing or testing. Then it turns out to be very convenient to use some of those in the API you export to other modules, and you may or may not remember to remove them before deploying, so you end up losing any supposed benefit of encapsulation.