It's a good suggestion, I will speak for my self personally, in everything I do, I like to be realistic so that I don't end up being disappointed when things do not go the way I thought it or they should go...
The realistic issue here is that, no body knows what the future of bitcoin is like, there is no guarantee anywhere that if you are saving bitcoins for your child, by the time he becomes a teen, the price of bitcoin might or will have reached $500k, we  can only guess the future price of bitcoin, nothing is sure or certain.

So what I am saying in essence is that if anybody wants to save in bitcoin for their child, they should get rid of this mindset of bitcoin is so and so, and they expect it to be so and so in so so year, this is to avoid disappointments, 1 bitcoin wil always be 1 bitcoin, the face that fiat currencies are heavily loosing their purchasing power due to heavy inflation is a enough reason already to keep ones money in bitcoin, get rid of the price mentality, because if you keep calculating the price of bitcoin in USD, you might end up disappointed some day when bitcoin fails to reach a USD price you anticipated.