Problem is your parents or anyone else in the mainstream still won't use it. There is no denomination and they won't have any confidence that it won't be hacked. There is a reason that physical assets in private vaults are fiat and precious metals... their value is self-evident with the printed or forged denomination and therefore these assets are completely trusted and fungible by everyone. Once you cloak the value in a card behind proprietary tech, all bets are off for mainstream adoption.