They say that it is not the best way save money, they can be correct and they may be wrong. This depends on how we see things in the future and our perspective and belief on where bitcoin is going soon.
So this isn't only about saving but also investing. Give your kids real property and that can be inherited forever unless they are going to sell it if they are in dire situation that its their solution to their problem.
I agree. Bitcoin may be the future, but since fiat is what we have right now, why not open a bank account solely for your kids, then buy a property, and to make the deal sweeter, store some bitcoins in a separate wallet. By the time they turned 18 they'd be rich and have a better life.