Atom itself doesn't need coffee-script, but many of its contributed atom packages (which can be downloaded from within atom) assume coffee-script to be installed, as they need it for their installation.
Can you provide an example of what breaks and how please? APM has coffee-script as a dependency and AFAIK packages perform transpilation on installation and don't need coffee-script at runtime.
Typically, the installation of an atom package will fail with an already reported bug on Github, where the coffee executable is not found. I installed coffee-script and tried installing the atom package again, and it worked. I can't reproduce it anymore, though.
I'm a bit reluctant to add an explicit global dep on coffee, as APM already pulls it in, and everything should work as is. Upstream atom does not require system-wide coffee-script either. Could you please post the error output, as well as the name of the package you're trying to install? Next time this happens that is. You may be able to trigger this by removing the ~/.atom/compile-cache directory. Thanks.
I'm closing this with WONTFIX: there is no need for a global dep on coffeescript, it is included with apm.
