here are three suggestions for the subito principle:

1)
when paying at the subito checkout, you have to tap on continue x times without scanning vouchers (GS) and vouchers (WS).
-> why must a distinction be made between the GS and WS? the system could recognize independently whether a WS and or GS has been read in and display this.

2)
once you have paid at the station, the receipt appears - 3s later the 2x cumulus voucher - possibly...
from a certain amount or so a voucher comes, or not, i don't know
->print the voucher together with the receipt or display "you will receive a voucher"
i have already seen 3-4 people simply leave after the receipt was there - or just stop and say "is there anything else coming?"

3)
the scanner has a great screen, is connected to the system via wifi and knows me (cumulus).
-> i would like to be able to create my shopping list on my pc at home (or app if mobile).
BSP: i'm on my way to work on the suburban train and my colleague mentions tree nuts - i get a craving for tree nuts - i type tree nuts into my app, get product suggestions and tap it.
the next day at migros, i take the scanner and lo and behold: her shopping list: tree nuts, tomatoes, kitchen paper, vegan hamburgers - ha, and this without a note that you leave at home anyway

saved in the app with a recipe and the number of people + meal time, you could have a shopping list created, send the recipe to the printer with e print and as soon as all the necessary ingredients have been bought, you get a message that the recipe is complete. the app then reminds you that you should start cooking slowly. (no, just no integration into the cell phone for recording via app - that's useless in terms of usability!)

i will gladly accept vouchers if this is implemented...