Is this actually the case though? Even if your card is taken by the staff and you don't see being charged, you are still being charged and some entity is processing the payment. I find it hard to believe that there are no fees just because terminal is stationary.
And that is considered "cheap"! By contrast, in the European Union there's a cap of 0.3% on credit card interchange rates and 0.2% on debit. Of course that's just the raw interchange fee; a small merchant has to pay more than that to its card processor, but there are all-inclusive, Square-like offers for debit card processing fees below 1% for small merchants, and larger ones manage to keep both debit and credit processing cost way below 1%.
So the "comfort" of being able to hand over your credit card to someone who takes it out of view and possibly does unauthorized stuff with it increases prices of all the stuff you buy by roughly 2-3%.