Why doesn't that exist, Amazon Prime?

Wait, prime had no way to buy it par card, like with the Netflix cards

Sure you can buy voucher cards and prepaid cards, there are everywhere where there are also Netflix cards.

To watch prime video

You can also pay for your Prime subscription with prepaid cards.

You can only with a credit card or bank account

Nee never existed. Something like that only came with Netflix and stayed with it.