How are credit cards not the most terrible thing ever? Some random number with an expiry date and an additional number is the key to your wealth (subject to a l

How are credit cards not the most terrible thing ever? Some random number with an expiry date and an additional number is the key to your wealth (subject to a lot of terms and conditions)? I would rather go with a cryptography based solution, where all the terms and conditions are open source code, all day