Wouldn’t that also just be a broken “half-functioning interface” as mentioned in the article?

“Half-functioning” while not as good as “functioning” is still better than “non-functioning”. Remember that “JS disabled” doesn’t just refer to the experience of paranoid nerds but also people on dodgy mobile connections.

Ideally you should provide the full functionality without JS but because of real world constraints that just isn’t feasible for every project. But in most projects you can provide 80% of the functionality with 20% of the effort.