[lxgr]

You're out of $400 of liquidity (until the issuer provisionally credits your account, which they are required for credit and debit alike) either way.

The only difference is lost interest payments for these ~5 business days (which the issuer might even have to reimburse as well; I'm not too sure about that though), as well as not being able to pay for cash-only expenses using the money in your bank account.

Also, nobody is saying that people can only have one single bank account, and a debit card linked to it with no spending limit attached to it.

[scarface74]

Few people with decent credit have a card that has a credit limit that comes anywhere near their monthly spending requirements.