Why build your app in Flutter
Flutter compiles one codebase into native Android and iOS apps. For most business apps that means one build, one set of fixes and one release process instead of two, which is why every package here is built in Flutter. You still get two real store apps, not a website wrapped in an app.
Native-only development still makes sense for some products, for example apps that depend heavily on platform-specific hardware features. If that is your case, I will say so during scoping rather than force it into Flutter.