On an italian highspeed train where the ticket was tied to a specific train and seat there was the option for self check-in from within the app after boarding the train. This functionalily could be added to the SBB app for tickets which have a seat reservation attached, i.e. international trains. Then e.g. the italian ticket controllers would also not need to try to understand the SBB ticket (which ours totally failed and I cannot blame him for it).