If you buy a point-to-point ticket from Bern to Zurich you can use it once, to travel from Bern to Zurich, within the time of validity. If you buy a return point-to-point ticket you can travel once outward, and once return.
RedBaron No, point-to-point tickets can be used only once in each direction
So this only applies if it is a return ticket, not if it is a one way ticket…