What are the benefits of children teaching children?

Collaboration and tutoring are common learning methods focusing on student interaction. Homeschooling families with multiple children have the opportunity for the children to teach each other. Although this is proven to be helpful for both the learner and the "teacher", is it beneficial to both children to engage in this practice over time? Are the learners better off learning from their parent/instructor or independently?

I think interactions between learners is beneficial. However, there needs to also be ample amounts of time for independent learning and parent-led instruction. The reason for this is to expose the children to various learning situations and environments. Learning is a life-time endeavor requiring a wide repertoire of strategies.