It was one of the tools that allowed me to maintain healthy credit card usage habits. In my idle time when messing around on my phone I’d gotten into the habit of just transferring money from my checking account to my credit card, often in excess of my actual balance, so as to cover “pending” purchases.
Not only will my bank no longer let me do that, just to twist the knife a bit, they will let me make multiple payments totaling the pending total due so long as no individual payment exceeds my actual balance.
So it’s not that they can no longer handle negative balances on the card, it’s just that they’ve half-ass made the interface disallow it.
All cards calculate interest per day. That’s the standard formula. They only charge you the sum interest at the end of the month when your billing cycle ends.
https://www.nerdwallet.com/article/credit-cards/how-is-credit-card-interest-calculated
This becomes apparent if you’ve ever paid a card off really early, and then still been charged interest even though you’ve had a zero balance one or two weeks before the billing cycle ended.
No, not on balances immediately after the time of purchase, but on balances that remain unpaid after a starement’s due date.
Directly from the page you linked: