Worse than that - people will start tagging "this value is a Date" via comments, and you'll need to parse ad-hoc tags in the comments to decode the data. People already do tagging in-band, but at least it's in-band and you don't have to write a custom parser.

HTML and JS both have comments, I don't see the problem

> Could you imagine hitting a rest api and like 25% of the bytes are comments? lol

That's pretty much what already happens. Getting a numeric value like "120" by serializing it through JSON takes three bytes. Getting the same value through a less flagrantly wasteful format would take one.

I guess that's more than 25%. In the abstract ASCII integers are about 50% waste. ASCII labels for the values you're transferring are 100% waste; those labels literally are comments.

If you're worried about wasting bandwidth on comments, JSON shouldn't be a format you ever consider, for any purpose.

lol