JSON Advantages

JSON is more compact than other representations, such as XML

JSON is inherently a Unicode-supporting format (but it expects files to be in UTF-8 encoding).

It is faster to generate and parse JSON than XML. JSON it's JS Object Notation, which means it can be recognized natively by JavaScript. 

There is broad support JSON in many different programming languages

It is generally easier to general JSON than XML, especially from languages like JavaScript and Python,

JSON disadvantages

JSON cannot compactly represent complex object relations, such as one-to-one, one-to-many, and rings

Advantage of SparkSQL over traditional Spark

Compared with chained transformations, SQL is an easier language for many data scientists.

SQL allows very complicated analytical operations to be succinctly described.

SparkSQL allows many analysis jobs designed for use with MySQL or Oracle to be moved to Spark with relatively few problems.