And the bad boys and girls can still hack CRA and if they defraud you using the data they stole is CRA still liable in spite of your paper-based filing?

You will have to prove a lot of "facts" to win that lawsuit. Especially since your social number(s), email, phone, whatsapp, etc are all public info already.

Recall a few years ago an uneducated hacker ("script kiddie") got part way into a CRA website and they took the whole website down for a week. (The attacker was caught, and prosecuted iirc.)