Having a JSON file handle a form schema I provide abstracts away directly building the form myself with actual tech supported by most browsers, hence why I call it abstraction.
I usually only use stuff that either is raw Js, HTML, CSS or whatever builds on top of it. Never something that introduces some DSL and generates files for said environments.
Edit: Incidentally, I tend to treat "code made by an LLM" and "external dependencies" pretty much the same. Pretty low trust, with a strong interface between it and any code that matters