The anatomy of a Godot API call
So the decision for slow interop is caused by choosing to have parity between GDScript and C# because the former forces the types to be heap-allocated...and community might dislike a performance-friendly change which will break the parity in favour of C#.To be honest, if Godot embraces it becoming the Noah's Ark for Unity developers and prioritizes C# over GDScript to improve performance, it could be good both for Godot and C# ecosystems, and more emphasis on the ability to use very rich selection of libraries written for .NET would not hurt either.