The banks have to because they need their account holders to use their debit card in confidence, otherwise, people who tend to be nervous nellies over everything and need their hands held won't use them. Obviously, it is in the banks interest because the cost per transaction is cheaper via debit card, then checks or cash.
I won't bore you with my story, but BoA replaced my money on the spot and it was not a small amount, either. It is the only time, I have had a problem out of thousands of transactions.
They’ll cover it until they don’t.
No downside to using a credit card exclusively.
Actually, it’s not “cheaper” for the banks that their customers use their debit cards. It’s because they get their own “skim” from every single transaction. The business it is used at is charged around 2% for every debit card and credit card transaction. That percentage goes to the bank. It is in their interest that EVERYONE use a card for EVERYTHING.