Hello jtsorlinis
The Saver Day Pass is valid everywhere where the GA travel card offers 100% coverage (so called “GA-Bereich”). On routes where the GA is partially accepted or not accepted, the full fare Saver Day Pass is not valid.
When you combine the Saver Day Pass with the Half Fare Card, on routes where the Saver Day Pass is not accepted, the Half Fare Card might offer a reduction.
You can find the validity map here: all red, black, blue, or yellow solid lines indicate that the Saver Day Pass is granting free access. Dotted lines mean, the full fare Saver Day Pass is not valid. Holders of the (Swiss) Half Fare Card or GA will benefit from a discount. Grey lines mean, no discount at all.
https://www.sbb.ch/content/dam/internet/sbb/de/abos-billette/abonnemente/Geltungsbereichskarte.pdf.sbbdownload.pdf
Does that answer your question?
Kind regards,
Roland