From 4.0.0-nullsafety.1 version, it supports null-safety. From 3.0.0 version, it supports exporting your flutter code to json code. please check How to write the json ...
Why should you use flutter_i18n? The main goal of flutter_i18n is to simplify the i18n process in Flutter. I would like to recreate the same experience that you have with the Angular i18n: simple json ...