whereas Bitcoin fees are clear cut, simple, and transparent?

the quoted material is not saying it's cheaper to process a Bitcoin transaction than a credit card. it's saying the Bitcoin fees are less now than the Bitcoin fees were when they started. probably because they found a "better" exchange to handle it for them... an exchange which totally won't go dark on them and vanish their holdings with no recourse because lmao Bitcoin.

meanwhile, current interchange fees for MC & Visa are posted online and change, at most, twice yearly.

ex: https://usa.visa.com/support/small-business/regulations-fees.html

and these vendors can/do negotiate reimbursements against these fees for a high volume of transactions.

is it a.scam? sure. but Bitcoin is not an improvement.

high volume vendors, like a national restaurant chain, pay closer to 1%. I was a tiny, low volume (1-2 transactions a year, less than $1000/yr) and I never paid more than 2.5% for a card payment.