In football, coaches will put cones on the ground and ask you to dribble the ball around them. This is supposed to improve your accuracy and fluency, but nobody believes that the purpose of this drill is to get better at dribbling around cones. Everybody understands that the purpose is a transfer of skills to a similar but different situation in a real football game.
Things are not so clear when it comes to the teaching of writing. It's pretty typical for writing textbooks and writing teachers to make claims like: "There are two ways of organizing a compare/contrast essay: the common traits method or the similarities/differences method." Some of them might admit that there are many ways but then present "two of the most common" or some hedge to that effect. What students typically understand from this is: this is how you play the game.
Here's what I tell my students they really mean: When you're practicing to be a better writer, sometimes following a formula or copying a structure is a useful exercise. This simplifies things for you by allowing you to focus on certain elements and ignore others. Don't confuse the exercise with the game though. It's not common for academics, journalists, bloggers, or other self-directed writers to produce five-paragraph compare/contrast essays using "the similarities/differences method." Neither should this be your goal.