Making in-page elements or containers give more flexibility to the user so that he can move or drag stuff as per requirement.
In jQuery UI we are pretty much aware of a Draggable function which makes thing a lot easier. jQuery is still loved due to its plug play and enjoyable way of work. Today is the era of AngularJS, now nobody talks about jQuery they simply jump in MV* frameworks and only AngularJS comes to the rescue.
