I can't imagine CoffeeScript will see much adoption these days as most people seem to think ES6+ is "good enough". I miss how concise functions are in CoffeeScript and also miss being able to do object literals without the braces. But there's no chance at all in convincing my team to adopt it, as modern JS really is "good enough".
I honestly think both ES6, Coffee and the like are going in the absolute wrong direction. Every release replaces more keywords with punctuation marks. That's the reason the community abandoned Perl. How much productivity do I gain by replacing "function()" with "() =>"? Round and round we go. Before anyone tells me, yes I know the semantics are slightly different, but muddling the semantics with arcane syntax is not…
I can't think of any other examples. Closures get used heavily in JS and arrow functions do make their use quicker and more concise, as well as fixing `this`. Compared to other languages like Scala, OCaml, Elm and Haskell, with symbols for functional combination and pipelining, pattern matching, and whatever you call the thing where you can miss out parameters and use underscores in function bodies in Scala ... JS is relatively light on symbols.