i understand your concern about my way to secure my passphrase. For me its a though about how high the risk is. You never can get a complete safe place for it, you only can make it harder to get the phrase.
I only can speak about germany. I know the problems because i work for a bank ( yes i work for the traditional system and support the new one i know.) . The risk that a bank rush and a collapse of the credit unions and trusted saving banks will happen in germany is very very low and even then the bank cant open my safe deposit box without me - ok they can if they blow up there own strongroom, but then they would even destroy the paper with the passphrase on it.
If i get notice that they try to open it or that they wont let me open my own safe deposit box, i just create a new wallet and send the ADA i have to the new one.
Sooo in fact if someone would get into the strongroom, find exactly my safe deposit box around thousands of them, can open it without destroying it and know what to do with 24 words that are written on a paper and this all without get noticed from me, my bank or the police then i could say he have earned the money.