Is good to teach our kids about the value of money and how to secure our money from intruders or scammers, but then I am kind of concerned about the age of your child.
7 years old child is not old enough to truly understand financial management and the true value of money, and he/she can easily be carried away there by exposing vital information.
Our kids are no doubt the future, and what we have today will be carried by them tomorrow. So there is no point in keeping them away from bitcoin.
Few things we need to understand in this regard are that with Bitcoin, kids can gain access to age restricted sites like gambling, etc. Since crypto based sites are open for everyone.
We may start telling kids about Bitcoin once they are a bit grown up and use Bitcoin under the supervision of parents.