I explained there is electronic money on it and it will be his one day. Went through the process of wiping it and restoring with the seed. But reminded him never ever tell anyone about it is our secret.
He's a smart kid and was amazed at how it's secured by an extremely complex code and that no one can steal the money you can take it anywhere and it's safer than a bank because the ledger is a bank itself (i know that's not quite correct but still). I didn't tell him how much are on there but told him one day it will be extremely valuable that's why I'm telling him about it is for him when he grows up.
Later that day we talked about how to secure the seed and printing it on a metal plate. He thinks it is so cool.
It amazed me how a child instantly understood it and showed how cryptos are for the future generations not us. We are early adopters so buy at least 1 bitcoin for your kids. Just might set them up for life.