That's good for you and your child, that means you have to teach and introduce bitcoin to your child. But kids usually just want to have fun and a pedestal to learn. So you should not force them to know and do what you do in bitcoin. Let them do what they want. If you want to keep bitcoin for your child but they do not want to know, you can entrust the bitcoin you keep to your relatives and give it to him to give it to your son someday.
Saving is always a good thing to do in all of it sides, and if someone will take the saving method to the new era currency or the cryptocurrency which can somehow be a part of future transactions, businesses and investment could help someone to get ready on the development and the changes could happened in the future. And starting to save bitcoin for the future of your children can also be a good investment for them in the their education, needs and in daily basis transactions.