The original reasoning: GDScript is the default path in Godot, nearly all docs and community examples use it, and the engine integration is tighter (signals, exports, scene tree). C# still has some gaps — no web export, no GDExtension bindings.
But you're right that from the LLM side, C# flips the core problem. Strong training data, static typing for better compiler feedback, interfaces for clean architecture. The context window savings from not loading a custom language spec could be significant.
Main thing I'd want to test is whether headless scene building — the core of the pipeline — works as smoothly in C#. Going to experiment with this.