One real-world scenario is the numismatics and bullion world. Especially on bullion items, there's very narrow margins, and I'd expect a high transaction-rever

One real-world scenario is the numismatics and bullion world. Especially on bullion items, there's very narrow margins, and I'd expect a high transaction-reversal risk (i. e. demanding refunds or charging back if the price of gold dropped after purchase). In practice, this means that many dealers will charge a higher price for using non-cash payment systems. At least in the US, some dealers will even be explicitly cash-only. Six one-ounce gold coins would get you over USD/EUR 10,000, and isn't that exotic of a purchase in that context. A documented payment system might be viable for that scenario, if it was completely zero-cost to merchants and consumers, although some dealers might still not want the reversal risks. However, conjuring that would require major state intervention.