nothing new about that…after all the app is rendered in html, for that matter it will run on iPhone too..but if the app only runs on the firefox browser on Android, I don't see many people creating apps for that reason rather using Cordova.
The new part is that the app is automatically packaged into an APK (Android Package) file, so you can manage it (launch, restart, uninstall, reset data, switch between apps) just like other Android apps.
Android and iOS both offer "bookmark to home screen" features that include some of this functionality, but not all of it.
Even if web apps run in modern web browsers, there's a big chance that you would want your app to offer the same experience and integration as native apps on other platforms.
Using the Firefox runtime rather than Android Webview is great because the Firefox runtime is far faster than most phones's Webview implementations, and will continue to be updated.
