"But I can do everything I need in: ruby, python, php, java, ... !".
I hear you. And you are right! Node is no freaking unicorn that will come and do your work for you, sorry. It's just a tool, and it probably won't replace your regular tools completely, at least not for now. :: Understanding node.js
"Node.js is only suitable for writing small APIs, not for serious web sites or web applications".
The Downside of this approach is the use of two separate servers, adds more complexity. Using node.js with django is all about choosing an IPC method to communicate between two separate process, results in unnecisary compexity? I think the best way is simply for each layer to talk to the data base seperatly.