People have been doing that for a surprisingly long time. I think it was encouraged by the fact that CoffeeScript is immediately intelligible to a lot of JavaScript coders, and authors reckon that anyone who has trouble can just compile it and get fairly idiomatic JavaScript.
I actually wrote a bookmarklet a while back that would look for CoffeeScript snippets on a page and translate them for people who find it troublesome, but didn't end up doing much with it because I didn't feel like there was much interest.
criticisms of coffeescript aside (e.g. interstitial whitespace sensitivity), the code can't directly be applied in node (as far as i can tell, you can't tell node to run a coffeescript file directly using the `node <script>` syntax -- you have to use a framework or compile to js).
If you don't want to compile, assuming you have CoffeeScript installed, you can just run it with coffee instead of node and everything else works like normal.
remember: java is to javascript as pain is to painting.
it's not an apt comparison. You can directly write javascript and run it in your browser or in node (or test it out interactively in the node REPL).
I like to play with modules in node interactively (when relevant) because its easier to see what's going on and much easier to iterate (esp. in conjunction with the .load REPL command)