In Node.js you don't want a compile step. In the browser however that would probably be a better solution indeed.

no compile step needed in nodejs. Most third party languages can hack require so using the transpiled language requires no manual compilation.

Why don't you want a compile step?

Because a compile step is annoying when it's not strictly needed. In the browser you usually have some kind of build system for concatenation and minifying anyways.

With coffeescript, at least, there is no extra compile step from the user's point of view. You can run `coffee myapp.coffee` in the same way you would run `node myapp.js`