A coin can cost more effort than it is worth
A penny’s face value is tiny, but handling it still takes time and space. A cashier must count it, sort it, store it and keep enough small change on hand to complete cash transactions. Those steps do not shrink just because the coin buys little. The result is a mismatch: the penny remains part of the payment system while doing very little work for each person who handles it.
Machines make the mismatch visible
Automated payment equipment has to identify coins by their physical and electrical properties, then decide whether to accept them. A machine may reject a penny if its coin mechanism is not set up to take that denomination or if the coin fails the machine’s checks. For someone paying at a machine, a coin that is valid money but unusable there can mean switching payment methods or seeking assistance.
Cash makes every small difference matter
Card payments can record an exact amount without passing individual coins back and forth. Cash purchases require the buyer and seller to settle the total with notes and coins, so removing the penny from circulation would require a way to handle totals that do not end in five cents. Rounding rules determine who gains or loses a few cents on a particular transaction; the direction depends on how the total is rounded.
That is why the inconvenience is concentrated in ordinary moments: finding a penny, counting it, or discovering that a machine will not take it. A coin worth one cent can still demand more attention than its value seems to justify.
