Edit: Seems like it's not a problem anymore, can't wait to try again.
This will probably change in the future (I hope it does, and I really wish Godot just used WASM internally so any language that already compiled to it would work) but as of now it seems there's no point to using anything but GDScript or C#.
It's open source, of course, so that's to be expected, but it also means support for any language other than C# and GDScript is kind of a crapshoot.
Been writing my own application mostly using C++ for the core logic and main application logic using GDScript. The interfacing between C++ and GDScript is suprisingly easy once you set it up.
But yeah stuff like Rust support is depending on the maintainers of that code to update to support latest versions of Godot.
For small shops (ie low or no revenue), you only need to pay that when you're ready to actually ship/make a build.
Note that the costs are higher if you're revenue is huge, it goes up to like >$100/seat/month or similar IIRC, I think that kicks in if you're in the 7-figures of annual revenue.
It's not free, and it can get expensive -- but you have to do the math on what you get, how much each will cost you monetarily & in time / opportunity cost, etc. IMO Unreal looks pretty compelling, and if they had C# support we'd jump to it in a heartbeat; I really don't want to write C++ on a day-to-day basis. If Godot keeps it up, then it may be the answer, in another 18 months or so -- but probably not wholly a commercially viable option quite yet, especially for mid-to-small shops.
Sorry, I’ll get my coat.
Without going into specifics, I think the problem is that the core team don't actually make games, they just work on an engine, so they don't appreciate the problems that I faced. (The same problem that Unity has, but at least they have the time to listen to devs)
I really want to love Godot. But I worry that the risks are too great to jump from Unity.