One of the main issue with Flutter is that you can't embed a native view inside a flutter widget tree. This makes it limited as we can't have inline maps or custom video views.

There are people working on it. The progrss has been slow. I checked a couple of weeks ago and the issue was still open.

But as far as I know you can have a native view in its own activity.

Though not a blocker for simple apps which previously used Cordova or ionic, I don't think Flutter is ready to replace native development for immersive apps.

Embedding a native view in cross platform UI is possible with Xamarin and React Native, so they are more practical choice for certain types of apps that need this.