A language is a skill based subject. It is not like Science or Social Sciences for which understanding of concepts is more important. It is more like swimming, cycling or flying for which mere knowledge and understanding are not enough. The more you use them, the more proficient you become.
It is very important, therefore, that the learners are provided enough opportunities to practice the sub-skills like Reading, Listening, Speaking and Writing of the language. But the question is what is Reading and how is it different from the other sub-skills?
If we don’t understand the differences between these sub-skills, then the danger is the learning outcomes might get mixed up. We may assume we are teaching Reading or Listening but in reality we might be teaching Writing and vice versa.