Along with that they learn to play with more structure in a faster moving game. A lot of the young indigenous kids play in carnivals against men when their 14. It has its up and down side.It probably wouldn't work in the modern AFL itself, but its definitely a benefit in slightly less intense leagues.
I remember reading an interview with Neil Kerley where he said he started playing senior footy at 12 - 14. He said he got smashed but was working loading cement bags into trucks or something similar so he could handle the contact. He had heaps of physical strength including core etc etc I assume from that work so it probably made physical contact easier to deal with.