We can't normally teach kids about bitcoin. Why? First is that they don't know the value of money. They just sit around, play around, etc. They don't have the interest for the money. All they do is to ask their parents buy their wants or may I say toys which is the things they want so bad. If you can teach them, well it's great.
You're right. Btc and crypto, and money matters in general, aren't really for kids to understand yet. Well if you can make kids understand the value of hard earned money early on in their lives then that would be extremely good but only if they show interest in it. If not, then don't bother. It will come in time when they grow up that they'll need these money lessons