If you purchase an item on credit, it's the bank that makes the purchase. You then pay them back, 30 or 60 (or more) days later.
If there's a problem with the item, you can "return" it to the bank — after all, they own it! So in practise you can ask the shop for a refund, or you can ask the bank.
It is a stronger protection than a debit card chargeback.
As an example, I bought flight tickets from an obscure budget airline on a credit card. Months later, beyond the usual debit chargeback time limit, the airline went bankrupt — but my bank purchased that service, and isn't going to provide it! They refund immediately.
