Interesting - In the old days, I believe the handling costs for debit cards were fixed per transaction - something like 30p - which made them cheaper than cheques for most businesses. Visa and Mastercard used to charge fairly significant fees, I think - I seem to remember figures like 3-5% from my childhood.
Now -- if I'm correct from my very brief reading on the subject -- the overheads are always percentage-based, perhaps with an additional very small per-transaction charge of a few pence. There may be a small difference between credit and debit cards. But the charges are very small, almost always less than 1% for normal, even small, businesses. There is typically a small monthly rental overhead for owning a card-processing machine etc, but again, it's not substantial. People who are paying more should, I think, check whether they're getting the best deal. (Admittedly, systems designed for more infrequent, mobile and casual use, such as Stripe and Paypal, do charge a percent or two more.)
So, unless I've missed something, I agree with Terence - I don't have much sympathy for those complaining about the overheads a cashless society imposes on businesses! If you like, charge me £99.99 instead of £99 - I probably won't notice!
I also don't, personally, have privacy concerns, especially when it comes to ApplePay - I know they've gone out of their way to make transactions less trackable, and I guess Android may have done the same. So yes, Apple know more about me, but the merchants - I think - don't know really any more than if I'm using cash.
Do enlighten me if there's something I've missed, though.