The performance difference is noticable. I did React into a Web worker, and here are the performance results - http://blog.nparashuram.com/2016/02/using-webwork

The performance difference is noticable. I did React into a Web worker, and here are the performance results - http://blog.nparashuram.com/2016/02/using-webworkers-to-make-react-faster.html http://blog.nparashuram.com/2016/02/using-webworkers-to-make... Some of the other uses typically are - sort of flow control between the thread and the worker, so that only sufficient VDOM operations are sent across the thread. This basically leaves the UI thread to other things like GIF animations, redraw UI like buttons when user interacts with them, etc.