The domain experts all write C#, and I don’t have strong language preferences, so it’s easier for me to switch to C# than it is for them to switch to Go. There isn’t a real technology reason, it’s just team ergonomics.

And that is very smart decision making. Professional!

I'd be curious too, but one place might be cross-platform easy runtime shared library use. Go with non-Windows "plugins", or poor c-shared support w/ crappy Cgo that doesn't even work with MSVC, is very bad in this area. Of course I watch all the GitHub issues addressing these with hope, but it's clear this story in Go is terrible.