Why not, this is a good idea to build some portfolio for your kids at a very young age. If you are buying bitcoins for yourself, why not do so for you kids as well? At the moment banks are offering a lot of new savings schemes that are designed for young parents and grand parents. My parents where offered multiple savings accounts that lock you in for 18 years and then will be paid out to the child when it becomes of age. These schemes are designed to be able to pay for a new car, or university later. The big problem I have with them is that they cost a lot of commission today and offer almost no good interest rate in the long run. So why do you need the bank in the first place? To me it seems much better that you take care of the saving yourself and don't pay the bank for it. This gives us a lot of flexibility and we are not limited to save in only one account. When it comes to long periods of time I would recommend to invest in more risky assets. Putting some of the money in crypto currencies is a great idea, same goes for investment and real estate funds. Over 18 years all these products are going to offer better returns than a savings account.