Actually, for this example, there will not be a big difference between calling the Fastlane’s actions or the Gradle tasks. But if you want to publish the app on Google Play, it might be a bit harder to do this without Fastlane, because it already has an action that will publish your app. So, Fastlane just makes your life easier and that’s all :)
The point is that you have limited build time and it is useless to waste 5–30 minutes on waiting for the results.
The workflow is moved to "On Hold" state after the APKs were uploaded and a Test in Firebase Test Lab was created, so you will be able to check its results.
Hi Danny! Thank you for the question.
Fastlane is used for assembling the apks, running the unit and the instrumentation tests and for publishing the app, while the CircleCI's workflows determine what must be done for the different branches.