Why you are so optimistic that in the future the price of bitcoin will not make any gain of profit? the volatile characteristics of bitcoin price will always attached to the bitcoin, so if your children are traders bicoin in the future, they will still be able to gain earning by doing short trading. I hope bitcoin will always benefit for us all the time.
OP can make some savings in bitcoin for his children so that his kids can learn and trade with the bitcoins he left for them. The world is changing and you don't know what happens next. You cannot say that there will not be any good opportunities for them to make money. The next generation will be smarter than ours so don't worry about the future. Give your children peace of mind so they can have a good childhood.