Honestly this is a bit crazy to me. Why does processing a check require an extension of credit here in 2024? Why can't the banks validate the check and transfer

Honestly this is a bit crazy to me. Why does processing a check require an extension of credit here in 2024? Why can't the banks validate the check and transfer the money while you wait a few seconds at the teller window? All of the alternative fintech solutions can do that. The prepaid debit cards that unbanked people use instead can do that. Heck, even the blockchain can do it, for way too much money. Sure, back in the day of couriers carrying checks, it made sense that it might take a few days to know. Today, with the internet and electronic presentment, theoretically the whole system could be transparently replaced with one that can clear the vast majority of checks in seconds. Banks could offer checking accounts to even the least creditworthy people simply by not extending them any credit.