This popular imitative doesn't mandate the acceptance of cash. It mandates that the federal government must ensure that there are enough banknotes and coins and

This popular imitative doesn't mandate the acceptance of cash. It mandates that the federal government must ensure that there are enough banknotes and coins and that replacing the swiss franc with another currency must be done via popular vote. So it's not really that radical. The same organisation is already planning on another popular initiative that seems to go in the direction of mandating the acceptance of cash, but other than the title "Wer mit Bargeld bezahlen will, muss mit Bargeld bezahlen können" (roughly: if you want to pay with cash must be able to pay with cash) I can't find any details about it.