Why External Dependency Manager is distributed via dlls and not the source code?

### [REQUIRED] Please fill in the following fields:

* Unity editor version: 2020.3.38
* External Dependency Manager version: 1.2.170
* Source you installed EDM4U: Unity Package Manager (.unitypackage or Unity Package Manager)
* Features in External Dependency Manager in use: All (Android Resolver, iOS Resolver, VersionHandler, etc.)
* Plugins SDK in use: None (Firebase, Admob, Facebook, etc.)
* Platform you are using the Unity editor on: Mac (Mac, Windows, or Linux)

### [REQUIRED] Please describe the question here:

Why External Dependency Manager is not distributed via source code C# files like most of UPM packages do?
Why there are precompiled Google.XXX.dll's instead of source code files?
I genuinely think it would be very helpful to see exact source code to better understand how External Dependency Manager is actually working.