Every employee gets a receipt of how much they donated to which charities. Their donation also shows up in their year end paystub and W-2, both of which can be used in their tax returns.

On fees, it's typically just the network fee (e.g., Mastercard) that gets waived. The issuing bank, acquiring bank and the processor, still take a cut.

Bank transfers have too much friction. You wouldn't pay your corner store with a bank transfer. You'd rather swipe a card. It's why you carry around your bank card (which as a VISA or MC logo). You wouldn't pay for something on eBay with a bank transfer. You'd use PayPal. An interesting point is that both PayPal, VISA and Mastercard on the bank-end are really just a series of bank transfers wrapped with a more refined consumer/merchant interface (card / POS terminal).