I think part of the problem is that using GDExtension is like a two-way FFI. You can call (C++) extension functions from GDScript, but the same interface and ov

I think part of the problem is that using GDExtension is like a two-way FFI. You can call (C++) extension functions from GDScript, but the same interface and overhead are used to call (lib) Godot functions from the (C++) extension. AFAIK it's not like there's a <godot_impl.h> with engine functions that the compiler could inline. Here's a good example (look, there I am!), although it's a bit old and actually led to perf improvement: https://github.com/godotengine/godot-cpp/issues/1063 https://github.com/godotengine/godot-cpp/issues/1063