Nobody's really mixing versions, it transpiles ES6 and above to ES5. You don't have to use Babel, you only use it if you want to use the latest version of JS, E

Nobody's really mixing versions, it transpiles ES6 and above to ES5. You don't have to use Babel, you only use it if you want to use the latest version of JS, ES6. You can happily just use ES5, and many people do. Why use ES6? Firstly, it's a much better version, it solves a lot of problems (chief of all, it has a module system which ES5 doesn't have, not built in at least). Second, JS technology moves incredibly fast. ES6 will likely be supported 100% before the end of next year in all major browsers. So by then you can drop babel and just have raw code. Same with node. It was supposed to be fully implemented end of this year or thereabout, but it seems that implementing the module system is problematic. Sadly, it's the most important thing, without which you can't drop babel.