> Telling the user to write something in two different ways, 
    > depending on the argument being passed, isn't simple.

Huh? Sure it is.

Fun fact: Any algorithm you can write in JavaScript can also be written as a single function, full of nested whiles, if/elses, fors, labels and breaks ... does that mean you should write your entire program as a single function? Nope.

I'd like to think that CoffeeScript functions read better without an "ending delimiter":

    $('button').click ->
      alert "hello"

    # Or:

    app.get '/', (req, res) ->
      res.send 'Hello World'

In any case, if you're interested in using CoffeeScript, but the lack of an ending delimiter is putting you off -- I encourage you to add one in your fork.