Personally I hate tooling for one language written in another. I hate python used to generate C++. I hate go used to generate C++ or JavaScript. Every added language adds more knowledge needed to contribute.
For every 1000 JS developers and every 1000 Zig developers there are 25 that know both. Only those developers can modify the system.
Further, you double the dependencies. JS pulls in library to do X that requires 50 dependencies, Zig pulls in a library to do X that requires 50 dependencies.
You also have 2 toolchains to maintain.
And you have 2 dev environments to maintain. Get all your editors/IDEs to understand both language. Get double your checkers, double your testing, etc etc.
You effectively increase the tech debt exponentially.
For every 1000 JS developers and every 1000 Zig developers there are 25 that know both. Only those developers can modify the system.
Further, you double the dependencies. JS pulls in library to do X that requires 50 dependencies, Zig pulls in a library to do X that requires 50 dependencies.
You also have 2 toolchains to maintain.
And you have 2 dev environments to maintain. Get all your editors/IDEs to understand both language. Get double your checkers, double your testing, etc etc.
You effectively increase the tech debt exponentially.