There is yet another approach.
if you are hesitant to have your credit card numbers, debit card numbers, or passcodes for ANY site on your computer, you can choose to NOT save them on your computer at all.
I do not want my credit card numbers in computer-readable form on my computers at all. So I simply tell the Mac when it wants to save them, "No Thanks". This means I need to key them in each time they are used, but I do not find that a huge inconvenience. (For bank account passwords, you would need to memorize and/or commit to paper copy in a safe place.)
Similarly when you Mac asks, "Save this password?" you can decline. If you have already committed them as a saved password once, you can use the Keychain Access utility to view, edit, and if you wish, remove selected passwords.
if you have questions about how to do that or any related topic, just post back.