I don't really understand the use of json support. Is it:
1. Getting normal SQL columns in and out in json format instead of normal SELECT output? Wrapping SQL output is something every database wrapper/ORM already does for you.
2. Storing json blobs of data in a dynamic way without having to predefine which columns (keys) are available and still being able to search with an index on the data attached to those keys. This would be very cool, but I don't understand how it would work when the data structure isn't defined in advance.
3. Just storing a json blob of data without any new indexing of that data at all. Basically nothing more than a BLOB with a new name.