Learning by teaching make us more comfortable, because I don't want to research knowledge. But we will also have the knowledge to do that, teachers sometimes do not fully.
Learning by teaching makes us comfortable, because they do not have the knowledge themselves. But we are aware of only the teacher. In some cases it may be incomplete.
Learning by teaching makes us more convenient than because you don't have to go to the knowledge. But we have knowledge only to the teacher. Which sometimes may be incomplete.