Launch day comes around, they’re nowhere to be seen - why? Well, they may have found another app, or decided they don’t need the app after all - say they lost interest in the diet / health kick.
I feel like app registrations would only work for “special” apps that don’t have close competitors or have a particular buzz - e.g. Threads, ChatGPT etc
EDIT: I’ve misunderstood - the app was supposed to auto-download on launch day. It didn’t. This story makes a lot more sense now! I assumed it just sent a push notification / email.