APK stands for Android Package Kit — it is the file format used to install any application on the Android operating system. Simply put, just as a .exe file installs software on a Windows computer, an APK file installs an app on an Android phone.
Not all types of apps are available on the Google Play Store. Many apps of certain kinds are distributed as APKs directly through the developer's official channel. The 70000 bat Android app is available exactly this way — through the official channel. There is also a separate app available for iOS.
The biggest advantage of using an APK is that the app stays directly on your phone, so you do not need to open a browser and visit the site every time. You receive notifications, loading is comparatively faster, and you save some mobile data. Playing the casino games on 70000 bat through the app is a more convenient experience.