This appears to be a sandbox game / engine, which probably has a lot less reason to use an existing engine like godot than a normal game since it would probably end up duplicating a lot of the development tools provided by something like godot anyway.

It also appears to be in pretty early development.

So, even if it's a big project I'm not sure it's notable in the same way it would be if a major commercial game that had already been released using godot was switching off it of for some reason?