Are you building something with kewl JavaScript that couldn't exist without it?

A lot of people are working with various JavaScript technologies. JavaScript alpha males keep banging terms like generators, promises and reactive JavaScript. I'm sure this is all fine and in some ways better than what we've had. I'm just wondering are you building something that couldn't be built with jQuery / Mootools / PHP / Perl / Whatever old thing? Is it all just the same thing built in a better (or just more complex) way?