Actually it's a bit easy to teach kids about bitcoin, because it's same like teaching kids about money. The important is tell the kids that bitcoin same as money works, just tell the kids about and how is bitcoin works, don't tell them how to earn bitcoins.
You can certainly argue that bitcoin as fiat money in general, but you can not tell a small child about how the bitcoin itself, of course it will make them dizzy, and they will not understand it