Backbone.js is a pointless piece of code!
If you need a framework for your web application, do yourself a favor and stay away.
The reason behind Backbone.js success is, mostly, the ignorance of its users.
If libraries help closing gaps and filling holes, infrastructures serve as the foundation of applications. They are meant to help you maintain a sane, well formed, and scalable code base. Backbone won't do this for you. On the contrary! The lack of clear separation between areas of responsibility often, even though unintentionally, encourage you to cook spaghetti.
Take a look at this quote from Backbone’s site:
“Different implementations of the Model-View-Controller pattern tend to disagree about the definition of a controller. If it helps any, in Backbone, the view class can also be thought of as a kind of controller, dispatching events that originate from the UI...”
If this isn’t a red light then what is?