In my opinion, JSON is not the best format and has some problems. Lack of comments is one of the reasons, as they mention in there. Another is the lack of trailing commas (optional trailing commas would be useful for manually written files). However, these are problems with the syntax, and there are also problems with the data, such as a lack of a proper integer type, lack of Infinity and NaN, lack of support for character sets other than Unicode (and ASCII), lack of proper octet string type, etc.
Comments
In my opinion, JSON is not the best format and has some problems. Lack of comments is one of the reasons, as they mention in there. Another is the lack of trailing commas (optional trailing commas would be useful for manually written files). However, these are problems with the syntax, and there are also problems with the data, such as a lack of a proper integer type, lack of Infinity and NaN, lack of support for character sets other than Unicode (and ASCII), lack of proper octet string type, etc.