By the way:
This week i was up for a visit to the bank. A bank of which i am not a customer of.
As i don't really want to keep my seeds and (future) paper wallets at home, i asked for the price of a safe and if the contents are insured an all.
Mr. bankster asked me about the value and physical size of the entities i plan to put in there, so i said it would be foldable paper and a handful of items of the size of a matchbox. When he asked me for the value, which determines price and insurance, i said it is volatile in value and it might be anything between x1 (by current btc price) and x100 or even more in the next 30-50 years. So Mr. bankster said he has to contact his boss, who is the local manager of the safe, who in turn should call me on the same afternoon for speaking about details and possibilities.
I never heard of them again, no call from either of the two.

Well, this leaves me with the impression that safes seem to be a pain in the ass for banks (or this bank only, idk).
I found it quite unfair to base the price to rent a safe on the value of the content. Insurance, yes, that didn't surprise me that much. Seems like they out the amount which was estimated the value of the safe contents for. I can't just pay only for the safe and insurance covers the value of all that's in it, in case of physical desctruction, theft and loss.