As usual, some people want to undergo this risk in order to balance out other risks. For example, your bank account can be frozen under a variety of scenarios, even unjustly so. In such situation, it is better to have emergency cash at hand.

Diverse investments are good, but some liquidity is good as well. If you e.g. need to escape a starting civil war, things that can be carried on a person and have near universal acceptance are more valuable than a roll of blue chip stocks or a nice house that you cannot take with you. I have met people who escaped the siege of Sarajevo; cash and gold went a long way helping them out.

"As for cash only society, sorry but fuck that. "

That isn't something I proposed.

Countries like Italy cannot inflate their way out of debt anymore. ECB, at least officially, is trying to keep inflation low. But negative interest rates would help the heavily indebted countries to ease their debt service burden.

(If such constellation of parameters is sustainable, IDK, but that debt isn't going anywhere.)