So here’s where there might be some confusion, Binance consolidates a pool of different stable coins into 1 “BUSD” balance for its users[0]. Depositing any of these stablecoins into Binance will add to your BUSD balance, and you can withdraw from it as any stablecoin of your choice. What CZ is saying is that they ran out of USDC but have plenty of the other stablecoins instead. It sounds like they need to redeem the other stablecoins to fiat USD and send it to Circle to mint USDC with it, hence the talk about the bank.
[0]https://www.binance.com/en/support/announcement/binance-to-a...