It's common knowledge to anyone it applies to (merchants)
My point is (like others have written in this thread already) that those charges are passed on to consumers, who _don't know_ that they're paying for it and would in effect see lower prices on goods if the world moved to a Bitcoin transaction system.
I've used that argument with success when explaining "Why Bitcoin?". Actual savings do entice interest.
(I'm from a country where paying with cash is frowned upon and you're recommended to use credit/debit cards. They're touted as being the cheaper option due to less "hassle" with cash)