Wouldn't be awkward to use Haxe for a project that employed language specific APIs? It seems like the sweet spot would be using it to write basic libraries that had no external dependencies.
Platform specific APIs are awkward, which is why it's mainly used for writing games. NekoNME abstracts most of that away. I'm not so sure how easily it does node.js.
But the standard runtime for Haxe has been ported to the other languages in a fairly bulletproof way.
Any other reason why someone might want to use it?