(and we generally don't have to pay any conversion/transaction fee to make a purchase with a CC)
Actually we the consumer DO pay the tx fee. More specifically, the merchant pays it to the payment processor and their cost is added onto what we are paying for things - we just do not see it as a separate charge. The Merchants fee is generally anything from 2-6% of the transaction value. That is how/why some (local of course) merchants will give a discount for using cash vs credit/debit cards.
Actually, you're wrong. The merchants will usually not charge the transaction fee to the customers.
Not from what I've seen in the US. I've traveled for in work in every state and in all of them have often come across signs like I just saw today in my local doughnut shop:
All credit/debit cards are +3.5% of total
Same for the local small hardware stores like Ace, TruValue, etc. Large stores do not give the discount and pocket their usual tx fee when folks pay with cash.
Our company accepts credit cards for orders and the cc card companies want 4% of the transaction which we add to a customers order. If they pay with check/wire they save the 4%. Tx fees is how the cc companies make their money.