I don't download random business apps, and I live in a pretty tech heavy area, but I've never encountered a parking lot where I couldn't pay at a kiosk or booth. What I do encounter sometimes are friends who "have to" download the app because they're used to the convenience of app-based payments, or because they don't feel a need to carry cash.

I strongly feel that the convenience vs. annoyance is heavily tilted towards the convenience side, and I think people who feel otherwise are just not noticing all the ways that having a PC in their pocket makes their lives easier.