I had the same experience in Belfort, France. I had to download an app, create an account, buy tickets, and scan a qr code when boarding the bus. It was super awkward and for clueless tourists like me (even though I used to live there, where are my beloved paper tickets!!) it's pretty frustrating to try to figure it out while people are getting grumbly because they can't board the bus because I'm in the way with my massive suitcase.
Oh and the delicious irony, I got an email yesterday from the bus company saying that the developers went bankrupt and the app is no longer maintained. What a bloody joke!
So I guess for places that force an app on public transport users, one can only hope that app developers go bankrupt.