… you'll surely learn from their mistakes!
Yes, but teachers must also learn from their mistakes.
Teaching provides greater opportunity for learning – researching, preparation, understanding the student (human behaviour), understanding human interaction, how people learn, remember, recall, and apply knowledge, etc, etc.
To benefit from this process the teacher has to reflect on all of these aspects.
Who should teach? Everyone should be a teacher.
A Captain (senior team member) should instruct his crew, setting an example and providing explanation. A junior, can self instruct, looking, learning, and preparing their own 'lessons'; individuals should not overlook opportunities to ‘teach’ as a means of improving performance and experience.