No doubt a great idea from your side for ones children.Actually it will make any one tension free from the future of the children and whatever kind of money the children want in the future one can give it to them in the shape of BTC.
I've put a couple away for our first born recently, for me its a fairly safe investment with huge growth potential!
I agree to this idea because this will very helpful to our childen especially their financial support to the school needed.
I think you are getting it all wrong, OP is not telling us that saving bitcoin is good for your sons and daughters and for whoever it is. The question is, how will you keep your coins so that it will still be usable in the future and that it will be safe?
Anyway, If we are talking big amount, and you want it to be safe from intruders in your house, better go to any well reputed bank and ask for a safety deposit box. It might cost you a penny but atleast it is safer there compared to your house.