I like to dabble with Node, but I find its immaturity and ever changing nature make it a moving target. It’s fine for a quick point tool. And it’s simplicity make it great for prototypes But for larger projects Ruby and Php seem much more practical and less plagued by tool/version/library mismatch.
In other words: the benefits of new features can often be outweighed by the cost of change. The scale of the job at hand plays a part too.
Swift is in exactly the same situation. If I were to build a small iPhone app today I wouldn’t hesitate to use Swift. But for larger development and desktop apps it seems that it’s modern features are hardly worth the cost of rewriting code. My current project development began a little more than a year ago. In that time I would have had to rewrite three times just to keep pace with the language. I like to write code, but not that much.