What everyone says above is fine, especially Gamma and others with regard to "goon" as rudder VS J stroke. For beginners first learning to go forward with some modicum of control to where they want to go in a straight line, the thumb up goon is a rudder that will get them there. Teaching that method to beginners is often done as a confidence builder for getting in control of the canoe for forward direction. The trick after that is accomplished is to transition them comfortably to a proper thumbs down J, which will then lend itself much better to transitioning the paddle to other fine control or more advanced strokes, as well as minimizing the need for an end of stroke pause to drag the goon rudder behind you. The J, initially feeling unnatural, will become automatic and primary with practice.
I also note that at the end of the stroke, the paddle is lifting water, which is unnecessary and a sapper of energy after a long day of paddling. Most of the power of a stroke is obtained in the first 18-24 inches after the catch, and dragging the paddle back beyond the hip is soething else to work on avoiding.