I suppose mostly superficial reasons such as liking the keyword syntax better that using string keys in json, but also the richer set of data types (like sets),

I suppose mostly superficial reasons such as liking the keyword syntax better that using string keys in json, but also the richer set of data types (like sets), although that mostly doesn’t matter in practice, but it is very nice when using Clojure since the Clojure types just work. As an interchange or storage format it’s also nice to be able to store Clojure types and get them back the way they were out in, which if using json you would lose some information. Mainly it’s just personal taste and no deep reasons.