Earlier quoted context omitted.
It is not ready imo. Someone correct me if I am wrong about any of this. Their custom scripting language is extremely slow to the point where I wouldn't consider using it. You can use C#, but if you download the c# version you get a warning on startup which states that this version isnt production ready. You can use C++, but I found the workflow here awkward, plus they just introduced it with 3.0. They are about to l…
Oh, come on, how many compute-intensive things you need to do in a game scripting language? GDscript is fast enough for scripting, C++ is there for the compute-intensive tasks you might do (though most of them are already implemented by the engine). C# on the other hand, is to attract Unity users that are too lazy to put in 30 minutes to go through GDscript's concepts. It's OK that it's there, but personally I found…
I strongly suspect that most people will write their entire game in an engines default language. Especially in this case where the much advertised best alternative (C#) gives you a warning on startup about not being production ready.
Yes, C# is probably integrated due to its success in Unity, but it's a sane choice. I would argue more so than GDScript. C# has better performance, tooling, support, not to mention an existing userbase of people who already know (and I'm sure many of whom like) the language.
Ignoring C#, they cannot be breaking their API for writing native code. I'm not sure if it was a one time thing, or if it will continue going into future releases, but they absolutely need to have stability if they want people to use their engine long term.