Hello Jahreviking
Believe me, the SBB staff is well aware that tourists do not have a photo on the app. Neither do all the locals, as you can use the SBB Mobile app as a guest as well.
And since e-tickets are personal, you have to show your physical passport or ID card along with your e-ticket.
And yes, without a physical ID your ticket is not valid and you have to pay for new tickets (a surcharge of CHF 90 per person would actually be due in addition as well).
It is clearly stated in the GTC, that you accepted when you have downloaded and installed the SBB Mobile app. See the tab ‘Profile’ > ‘Legal’ > ‘GTC’.
Best wishes,
Roland
