What a PWA can and cannot do on iPhone
PWAs on iOS can be excellent installable web apps, but they do not receive the same platform access as native apps. Design around the actual boundaries.
What a PWA is good at
A well-built PWA can provide an installable home-screen experience, offline caching, fast repeat navigation, push notifications in supported scenarios, camera/file input through web APIs, responsive layouts and a single codebase across browsers.
For business systems, dashboards, forms, catalogues, portals and many operational workflows, that is often enough.
Where native access still matters
A normal PWA should not be designed around direct access to iMessage/SMS history, phone call history, HealthKit, unrestricted background processing, full filesystem access or deep Siri/App Intents integration. Some browser APIs remain unavailable or more restricted on iOS than on other platforms.
If those capabilities are core requirements, a native or hybrid wrapper may be the right architecture.
Design graceful boundaries
Treat web capabilities as progressive enhancement. The core workflow should continue to work when notifications are disabled, the app is not installed, background execution is paused or a platform-specific API is unavailable.
PWA decisions should come from the workflow. Do not choose native because it sounds more serious, and do not choose PWA merely to avoid app-store work. Choose the minimum platform that reliably supports the required behaviour.
Turn the idea into a clear implementation plan.
Use TWE to structure requirements first. If you later want implementation, Valron can pick up the same brief.