I would agree that there is definitely a "cost" to handling cash - but it's not so easy to attribute as it is for an electronic transaction where you know the fee and it's charged when it's done, and available via the provider to the merchant.
Handling the cash, storing it (for example, between bank runs for possibly larger amounts), and taking to/from the bank (so possibly the time of an employee, or the owner's time) plus the risk for carrying cash and all that, but I guess managing the cash has a cost too - managing the "float" for each day's trade, accounting for all cash at end of day and reconciling with the register or accounting system etc.
Probably the less cash a business deals with is probably easier these days given these kinds of activities imo. I've certainly heard anecdotally that many smaller businesses can find it a PITA to do those accounting processes and regular bank runs (rather than what the bank may or may not charge for deposits). Don't some banks charge to count coins? I seem to recall something like that - but that may be just for personal use as opposed to business - I don't know.
I'm not against cash at all. I find it has its place. I carry a (small) amount with me just in case (<$100) and absolutely for a business that doesn't take eftpos/cards, or if their terminals are down then hey ripper. I think that happened last year sometime I was at a place and they asked for cash as their terminal was down. It was actually quite weird to pull it out of my wallet (all the dust that came out!
) and I had to laugh a bit at that, but it was fine of course. I'm not entirely pro the digital economy/cashless society - not so much for the people who don't want to be tracked and like black market transactions and under the counter payments, but more for the fact that if there is a technology fail (like we just had for many with Optus, or more simply a merchant issue) then you're in trouble. I reckon there will always be a place for cash, and should be,
However I prefer to use my points earning card. I pay it off promptly so have never paid an interest charge, and where it happens I accept the extra transaction costs for the (apparent) benefit of the card services - points, insurance, etc - but do understand that there IS a cost for this and it's a choice.