Not speaking for the parent, CoffeeScript is even worse than Javascript. The killer for me is indentation forming scope. If you accidentally indent your code incorrectly, like when you're copy/pasting from one file to another, you can change the scope of all of the variables within.
The other major problem I have with it is that it encourages us to go back to the class-based patterns that we've been trying to get away from.
Please. Coffee has its problems, but being white-space sensitive is not one of them. It's entirely a matter of personal preference, just like preferring {...} instead of begin...end or using '' instead of "" for strings; it's not even as significant as prefix vs. infix syntax, which does have some practical consequences. You get indentation based blocks in quite a lot of languages, Haskell, F#, Python, Nimrod, MoonScript and others and it works there, I see no reason (knowing them all) for it to be a problem in Coffee particular case (to be honest, Coffee allowing inconsistent indentation in a single file is a bad design decision, though).
Though you should always be careful when copy/pasting code.
I'm not sure how it encourages classes, I personally didn't even use classes at all for the first long period of my CoffeeScript life. And now only do sparingly.
The other major problem I have with it is that it encourages us to go back to the class-based patterns that we've been trying to get away from.