I've worked with the NDK/JNI and totally agree on the "poor soul" comment. If you're someone like Spotify who has enough money, supported platforms, and a complex enough app, then that method is likely a win.

But if you're only targeting Android and iOS, you'll likely get to market faster with something like React Native while still retaining native UIs. It'll certainly be better than Phonegap/Cordova/Ionic.