You remind me of those 1337 HTML "hackers" advocating to write HTML in Notepad. There are two different things knowledge and control of the code you write and efficiency of the coding itself. I've been writing HTML for 15 years and I always did it by hand. But never in Notepad — it is the most inefficient way to do it. A good editor with autocompletion, snippets, syntax highlighting will make you much more productive. The same applies to JS vs CS: CoffeeScript does not absolve you from need to know JavaScript, it just gives a way to write it in more productive (and fun) manner.