I'm aware that Swiss politics is sometimes difficult to understand if you grew up in other countries. In the case here, the title (and the Politico reporting) is at least misleading.
What we did vote on (and approve) is a new paragraph in the constitution which says "Die Schweizerische Nationalbank gewÃhrleistet die Bargeldversorgung" (roughly translates to "The Swiss National Bank ensures the supply of cash"). We did *not* vote about whether businesses (or private citizens) need to accept cash as well.
So while the vote ensures that there is always enough cash available for people who want to pay with cash, nothing ensures that they will be able to use that cash wherever they want. I doubt that a vote to force everybody to *accept* cash (instead of credit cards etc) would gather a majority.