In certain cases Cash takes on almost a freedom of speech importance. Government can just switch off the digital finances of any movement they don't like. Cash makes that harder.
As a topical counterpoint, governments can also just switch off the existing currency in favor of a new currency and create a cash scarcity crisis when theres not enough of the new currency in circulation. This is exactly the situation in Nigeria right now. See:
The parent I was responding to was not referring specifically to Switzerland, in fact they just said "Government" which is about as general as you can be. Further Nigeria is also wealthy, even if the concentration of wealth is in the hands of very few. Nigeria is the largest economy in Africa and 31st in the World by GDP.[1]
Cash represents a fundamental freedom to trade autonomously, without having it be approved by any third party. We've seen various attempts on the part of government and private payment processors to stop certain kinds of trade they don't like from happening. If you don't think they should be able to do this, you should support keeping cash, while developing freedom-respecting alternatives such as Monero to give future generations the right to do the same.
You can't eat bitcoin. So you have to exchange it for food. But unlike cash they don't accept it anywhere (and accepting cash everywhere is what this voting tries to keep a reality).
Also you can't access it in places without internet access or electricity (e.g. during wartime or as a refugee on the go).
There's a reason we moved away from the barter system. Cash would still be useful if it was rare and accepted by the government, though you should expect massive inflation. But something like gold would probably be a good contender as a new money.
Yes, the barter system damages any liquidity. You have to cease thinking in terms of any standard of value. Everything is this-for-that. Very hard to do on a large scale. I think the very concept of money would have to collapse.
