The reason to avoid running the CoffeeScript compiler in the browser is that it takes time to compile a script, time which can be easily saved for the user by s

The reason to avoid running the CoffeeScript compiler in the browser is that it takes time to compile a script, time which can be easily saved for the user by sending them a pre-compiled version. Of course running the CS compiler in the browser is great for development, but in a production environment every millisecond counts.