Also dont forget insurance for banknotes in a safe.
GP said it, negative interest rate, i.e. the bank charging you to hold on to your money when you have more than a certain amount (was it 100k or 25k CHF).
So if you put in 100k in the bank and wait a year, you'll be able to withdraw maybe 99.8k CHF. If you hoard 100x 1000 CHF notes, you'll still have 100k CHF. Sure in 1 year those 100k CHF will probably buy less Big Macs then the present, but the 200 CHF loss will mean even less Big Macs.
Cash at a bank is the best you can do in terms of risk free asset (for people in CH it's the equivalent of a bond allocation in a portfolio, just with higher return).
FWIW commercial banks have had negative interest rates for a few years now.
https://www.truewealth.ch/en/blog/negative-interest-switzerl...
If this were a party conversation, imagine me walking away rolling my eyes and shaking my head...
I saw one as a child. Most Canadians have not, as far as I know. An acquaintance of a friend of my father's had several, and my father was interested in numismatics, so he traded one for $100s. The implications of the man who had some "pinkies" (called so for their colour) being a biker with a facial scar didn't click into place until I was much older.