Oh wow, ok, for curiosity, when I have a Shell Gas Gift Card, or balance in Starbucks app, or walmart or dominos gift card, somehow that money is being held in a real bank? Just asking.
However, balances held by PayPal or Venmo? Yeah those are backed by a bank.
On the other hand, there are "universal gift cards" that work as a debit card and can be used anywhere (that supports that type of debit card). These would require a bank to hold the balance; when the card is used the money would go from that bank to the merchant's bank.