Nobody is compelling you to listen to what I wrote.
The day or two that the BANK owes money to the vendor is not really comparable to a case where the buyer got a loan from him. The buyer already fulfilled all of his obligations to the vendor and the remaining transaction is entirely between the vendor and the vendor's processor. That the processor witholds the money from the vendor has nothing to do with the buyer and is likely comparable to hilvani ad sheyavo bni with it being due to processing times going from the issuing bank to Visa to the card processor to the vendor. Even the CC fee charged by the vendor is not because of any loan between them but rather to defray costs of accepting the card and the risks involved. This is visible by the fact that there is no charge for paying by check even though it takes longer for the vendor to receive the money.
Is that necessarily true? What if the credit card processor shuts down the vendor's account and reverses all transactions before the funds were deposited? The vendor would then seek payment from the buyer again, indicating that the buyer's obligation isn't fully discharged until the vendor receives the funds. This scenario, though uncommon, highlights that the vendor is extending credit to the buyer.
In terms of covering costs, that only works if they charge what their actual costs are. If they really wanted to charge for risk, they would charge for check payments which is even riskier.