Hacker News Reader

A partial answer to your question, from the FAQ:

"What differs from other JavaScript Frameworks ?

Joshfire share the same will of easing Web Application development by introducing template engines, MVC coding style, magic UI binding to data and so on. However, until now, each framework had its own supported platforms: mobile webkit for some, recent desktop browsers for the others. Joshfire targets platforms ranging from IE6 to mobile devices, connected televisions and even headless devices."

you don't "need" it but it will save you time by already packing all glue and standard code for the supported platforms (SDKs, specific video components on TVs, scrolling on mobiles, code for handling keyboard/remote keystrokes, ...)

Especially since you still need XCode to deploy to iOS ..

If you mean deploy web apps to iOS, you are greatly mistaken. This is a web app framework.