The C# option of self-contained executables is very recent with VS2019 & VS2022 and was not available when Go came out in 2009.

Before that, you had extra steps of ClickOnce installer deployment or obscure AOT experiments that nobody was using in production. (Also as trivia, the new C#/NET6 self-contained executables don't work on Windows 7 and Server 2012. You still have to install .NET Framework runtime for those older systems.)

So during most of Go's history, the C# executable would get the following error if deployed on a computer without the .NET Framework runtime already installed:

https://www.google.com/search?q=%22This+application+requires...