TBH I don't know about the Hampden app, yet... it was just a general whinge! I remain to be convinced everything on phones is easier.
When Hampden is busy getting a data signal is almost impossible. Will the app work without data?
As an example I have had a few flights and train journeys recently where at the gate the app didn't function as no data signal, (or i wouldn't pay for data roaming) and screenshots or pdfs don't work. Worst is BA as the app always crashes.
Having a paper copy of my booking saved the day.