No problem at all with the idea of slowing the tempo; but I struggle with the WAY they pull it off. When you simply hold the ball or dribble out those first twenty seconds at the top, the defense gets a good rest, leaving them with plenty of energy to play tough D in that last ten seconds of the possession. I think it's a better idea to run your O, with no intent of scoring (unless an uncontested layup presents itself in the process), moving the defense and increasing the odds that they tire, make a mistake, and leave an opportunity for a wide open, high-percentage shot.