I find that these efforts to make something that is almost but not quite JSON to be counterproductive.

It means that something you can't tell if it's JSON or another format. You'll have some tools that can work with it, while other tools will choke because they expect valid JSON. Oh, someone just switched the quoting style so now your jq based automation is all broken.

And now you have to figure out which of these not-quite-JSON formats this is. Is it HuJSON/JWCC? Is it JSON5? Does my editor have a mode that supports this particular variant, or am I always going to be fighting with it?

And finally, having used HuJSON for Tailscale config: the issue isn't just things like comments and trailing commas, or quoting styles. JSON is just a kind of heavyweight and cumbersome syntax for writing config files. I find that I prefer writing a script to auto-generate my Tailscale config, because editing it by hand is cumbersome.

There are a number of other possible config file formats, with varying levels of JSON data model compatibility. YAML has its issues, but we've all learned to live with them by now. TOML isn't bad, though good luck remembering the array of tables syntax. KDL is pretty nice; it has a slightly different data model than JSON, but it's actually one that is somewhat better suited for config files.

I'd rather use any of these for config files than something that is almost, but not quite, JSON.