AFAICT, the only reason it's a point release are the breaking changes. Unfortunately, in order to stay relevant, coffeescript needs a major overhaul, though I must add that its biggest problem (the readability of tab denoted closures) is probably one that needs to be ultimately solved by the IDEs.
CoffeeScript’s intent, however, was never to be a superset of JavaScript. One of the guiding principles of CoffeeScript has been simplicity: not just removing JavaScript’s “bad parts,” but providing a cleaner, terser syntax that uses less punctuation and enforces indentation, to make code easier to read and reason about. Increased clarity leads to increased quality, and fewer bugs. This benefit of CoffeeScript remains, even in an ES2015+ world.
so, it's not really about "CoffeeScript's functionality" but more it's "style".