The fare indicated by default is the starting price of fares. You must be in the possession of the Swiss Half Fare Card (½) in order to buy tickets as low as indicated.
The second price is full fare (1/1) which applies if you do not have the Swiss Half Fare Card.
If you are interested in buying the Swiss Half Fare Card, you can check the ½ option under Settings > Travelers > Your profile and then all prices are half fare.
https://www.sbb.ch/en/leisure-holidays/inspiration/international-guests/swiss-halffare-card.html