I tried posting a comment to closed bug #12618, but there is more to the bug than just background color. The translucency is not being set as well.

Running React Native 0.46.4 on Windows 10 in an Android emulator, emulating a Google Pixel phone with Android version 7. Also tested on Moto E 2nd Gen phone running Android 5.1

In the first screenshot, you can clearly see a translucent StatusBar with no background color, even though I set the translucent property to false & backgroundColor to "blue".

In the second screenshot, I set hidden to true, and the StatusBar did infact hide, so the component is working (somewhat).