An Android app is a software application running on the Android platform. Because the Android platform is built for mobile devices, a typical Android app is designed for a smartphone or a tablet PC running on the Android OS.
WHY NATIVE ANDROID?
Developing one specific operating system allows developers to take advantage of its unique features and characteristics.
The Android operating system enables developers to design their own user interface (UI), whereas iOS has set-in-stone UI guidelines. The ability to customize UI and use additional widgets enables software developers to create unique user experiences.
The distinguishable features could include the type of swipes, gestures, or even the positioning of features. All these aspects contribute to how users interact with the app. When the app works in tandem with the rest of the operating system, the user experience is improved.