The usability win from 3 to other solutions is: Users don't have to wait until the next polling interval expired in order to get an update. In interactive appli

The usability win from 3 to other solutions is: Users don't have to wait until the next polling interval expired in order to get an update. In interactive applications users don't expect delays, so you should display updates in around 100ms. Achieving that with polling might not be feasible for some applications.