The issue is that these costs of handling cash are largely fixed - marginally, if your store takes $100 in cash, your cash-handling expenses and effort stay the

The issue is that these costs of handling cash are largely fixed - marginally, if your store takes $100 in cash, your cash-handling expenses and effort stay the same, but if you take $100 by card, your fees directly increase. You avoid the expenses of handling cash only if you don't take cash at all.