There are several reasons to upload artifacts to Testery:
You are uploading test assemblies because you are using a framework which requires compiled tests (e.g. SpecFlow, TestNG).
You are uploading test assemblies because you are unable to provide GitHub / BitBucket access.
You are uploading additional information about test runs that you'd like associated with the test run (e.g. code coverage reports).
Here are more details on how to upload artifacts using the Testery CLI