Why

Why a native bridge? Why not use just JavaScript?

The key difference with the native bridge is that you get a lot of the metadata handled automatically by the Google Analytics native library. This will include the device UUID, device model, viewport size, OS version etc.

You will only have to send in a few parameteres when tracking, e.g:

import { GoogleAnalyticsTracker } from 'react-native-google-analytics-bridge';
let tracker = new GoogleAnalyticsTracker('UA-12345-1');

tracker.trackScreenView('Home');
tracker.trackEvent('testcategory', 'testaction');