What many people don't realize is these cards are prepaid. Link to your bank account? All that means is you can link your bank account, to send fiat $ to buy crypto, which you then put on your card balance to go and spend, exchanging back to fiat for the final transaction

METAL (MTL) is the only one that I know of that is offering a full FDIC insured bank account when their card comes out. You can hold fiat and cryptos in it. It will have a routing number and all, just like any other bank account you have and will be capable of holding multiple types of crypto - http://initialcoinofferinglist.com/is-metalpay-mtl-the-omisego-for-america/