Swiss Card and Golden Pass Train

Hi tlk1951! The Swiss Card can only be used for either the shortest route (mentioned by the timetable) or the cheapest one from your border/airport to your destination. In this case, that's via Bern, Spiez and Interlaken. The Golden Pass route is a more expensive detour, so the Swiss Card isn't valid there.

Alternatively, you could check the Swiss Flexi Pass. This allows a couple of days of free traveling, including the first and last one of your stay, plus a 50% discount on remaining trips. Whether this is an option, depends on your further plans though.