Surely, we teach our g.children about money from as young as possible. Yes, now we have to take into account that we are living in a nearly cashless society - likely to become totally cashless within the next ten years. So, they get taught about that and how to manage it.
When I was a small child, back in the 1940's, I though my Mums purse was magical - and always had money in it. I learned soon enough that was not the case, so children, today, have to learn that ATM machines and plastic cards only have the money that is put into them. No magic involved.
Pre-loaded cards can be used soon enough for slightly older children, and by the time they reach their teens, a bank account can become theirs. Learning to think ahead and save for things they want ('need' in their language!), cannot be started too soon,.
I find it annoying that parents purchase quite expensive items for g.parents birthdays, xmas etc. and say it from the child. Far better for a much less pricey item is actually purchased by that child, which has been saved for out of their pocket monies. Nicer for the g.parents, and an excellent lesson for the child.
Once they are old enough to actually have their own credit/debit cars they need to learn problems that can ensure. How to watch out for scams, how to check their own account regularly to ensure no suspicious use (cloning). how to cope if their card is cloned.
Those that go off to Uni will have large sums of money at their disposal, although they have to know how to work out that most of it needs earmarking for fees, rent, food, etc. etc.
Even at a very young age, keeping a check on their own 'finances' is a wonderful less on adding and subtraction. AND, even very young children need to know that their adults do not have unlimited funds.