I'm as confused as you are why everyone is jumping on board the Javascript bandwagon. And not just on the desktop where there's the extra horsepower to run it, but also on very resource limited platforms such as phones. Why not Python? Isn't it easy to learn? Isn't it stable and robust? I'm coming from the Qt world, and Nokia's decision (which Digia is now forced to live with) to make QML/Javascript a requirement for QtQuick was mindbogglingly stupid. I have nothing against QML per se, but the arguments as to why C++ can't be used instead are downright silly.
But I know the reason why everyone is pushing Javascript: Because it's a web language. Look at the apps you can get for your Droid, the vast majority are little more than hastily ported web pages. Web developers are cheap, C++ developers are expensive. With HTML/QML/Whatever all you need to do to write an app is drag-n-drop some stuff around in an IDE and tie them together with some Javascript snippets. It's Visual Basic all over again!