Every time you create a new BTC wallet, you’ll get a 12 word 'recovery phrase' that needs to be noted down and hidden somewhere, which - to me at least - seems like a pretty gaping security gap. It doesn’t matter whether you write the words down and hide them in your attic, or stamp them on metal and bury them in your garden, the ‘master key’ to your wallet is still just sat somewhere, hoping that no-one finds it. If someone does find it, they can empty your account, and there’s no way you can stop them.
Firstly, many people would probably just throw your piece of paper where 12 word is stored.
Secondly, not many people know about Bitcoin or 12 word recovery phrase.
Thirdly, if someone wants to rob you and comes at you with knife on your neck, then your method is not gonna help to keep funds safe because in order to save your life, probably you'll have to tell the truth.
After all, best way to get safe recovery phrase is to generate it randomly but its weakness is that it's stored by humans who follow their logic to save it in a safe place.