Hello Joockoiyoa61
Because this type of ticket is calculated on kilometers, plus it includes a surcharge for the fast route from Olten to Bern, that explains the variable cost, while the GA has got a fixed price.
The cheapest way from ZUE to IO is, by the way, via Lucerne.
For example, commuters from Lucerne to Zug, or from Basel to Olten definitely use the Streckenabo because the GA is more expensive.
SBB is very transparent on their product website about that fact; see below, where it reads “it is worth …”.
This is why we always recommend to carefully compare the different ticket offers.
