The referenced "saver day pass" has interesting pricing, especially if you are traveling in 1st class and on a weekend--as low as 49Sfr (using a 1/2 fare card). The only minus is that you must pick a date far in advance and if the main reason for travel is to see spectacular scenery, you would "lose" if there is bad weather on the day you choose.
[A "regular" weekend 1st class day card is 127SFr and requires a 1/2 fare card.]
The day saver pass is very useful for people arriving in Switzerland.
I usually buy saver tickets to Zurich airport, as my flight basically fixes the train I'll take. That saves me quite a bit of money.
But I could not do this in the reverse. However this saver day pass is very useful when arriving, and heading eg. for Zermatt.