A Little Black Egg is a somewhat similar concept to this but, but it's a gas burner, while a kettle pizza insert is geared towards wood and charcoal. Because of this, it takes a different approach.
An LBE 'bends' superheated air up and over the pizza while an insert like this traps rising heat in a lower, thermally dense ceiling- at least when it's set up correctly with a top stone (a la Kenji).