Depending on which sources you believe, the cost of handling cash can actually exceed credit card merchant fees.
Many cashless businesses, including bars and restaurants, do it specifically because handling cash is expensive if you actually do a full accounting for it.
I get what she's say, but it is kind of a weird comparison, because Apple Pay is more-or-less payment network agnostic. You can pay via credit, debit, or transportation card (and possibly others that I haven't used) on Apple Pay.
In the US you even have Apple Cash which is pretty close to digital cash equivalent... not really workable for a business with the $2k/week limit though.
The reality is that for most businesses, accepting credit cards, with their fees, results in more revenue overall (more customers).
If your business is low volume, cash only makes more sense.
A lot? Not sure about that.
>I think he does do a few phone apps.
Not if he's cash only he's not.