Until you try to either cram it into Excel, work with different encodings or pass it around different software platforms (even your lang vs JS), no difference.
CSV has been abused a lot to make it work on conflicting use-cases, JSON handles a lot of misshaps happened with delimiter-separated record formats, like new-lines or bring-your-own-character encoding.
CSV has been abused a lot to make it work on conflicting use-cases, JSON handles a lot of misshaps happened with delimiter-separated record formats, like new-lines or bring-your-own-character encoding.