This is a simple thing:
When approaching a lesson, the skill is the goal, not the exercise to develop the skill.
For example, the prototypical five paragraph essay isn’t the point- understanding the structure of a position paper is.
As such, shouldn’t we be focused on the absolute best way to reach that goal? It seems the vast majority of the time is spent on developing the exercises, where it seems that focus would be better spent on finding more engaging ways to reach the goal.