PDF.js should also become a stand alone application

So I have been following the development of PDF.js
and it's been very cool.

I was thinking though that if possible we should also try to make a 
standalone application.

A way to beat the Mighty Adobe :)

Are there any technical limitations to this?
Why haven't we done this already?

I hope this can become reality.

Please tell me about any feedback, thoughts, criticisms, Invalids! :)