A typical crypto card acts in a similar way to your debit card. The vendor receives fiat cash into their account and not crypto.
A crypto card conveniently converts your crypto into cash which you can spend with the vendor through the card. You can also use crypto cards for ATM withdrawals if your service provider supports them.
The main difference is that you load your typical crypto card with cryptocurrencies. A debit card is pre-loaded with fiat currencies, and a credit card's transactions are paid off later with fiat.