Many if not most banks still distribute "Certificates of Deposit."
Actually, the mystery is "Why did we start handing out pretty pieces of paper and telling the customers they were important?" The answer to that is in the 1930s when banks wanted their "Certificates of Deposit" to be as impressive and substantial as the incredibly ornate stock certificates customers received when they invested in a corporation.
It's our fault that people believe the pieces of paper are important. They did not mean anything then and they don't mean anything now.
If your customer keeps a the receipt in his safe deposit box or with his important papers I can assure him that his heirs will track down every whiff of an asset they can locate.
_________________________
In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.