Very interesting... at face value it doesn't seem sustainable, extendable or consistent. Perhaps you need to elaborate more on what you mean about children teaching. That being said the "learn one, do one, teach one" model it great and I recall giving and receiving a lot of peer assistance when I was young.
children who are willing, teaching children of younger years certain skills they already know. Ofc they might need to learn some basics of how to teach in the first place. Its a bit meta but teaching as a first-class subject that is optional with hands on work during school would be really cool and be an incredibly strong indicator of people suitable for management/lead roles later up the track.
In my time at high school (UK equivalent) I don't remember receiving any peer assistance at all and its feels like we've missed a trick.