You tested the app in pre-production, everything looked stable, and the release went live.
Then a real user opened it on their phone, and things started breaking. The layout shifted, a button stopped responding, or the app crashed during launch.
This is exactly why real device testing matters. The challenge is that most real device testing platforms are built for large engineering teams with enterprise budgets, not solo developers or small teams trying to ship reliable apps without spending hundreds of dollars every month.