> The fact that json can represent a superset of tabular data structures that csv is specifically designed to represent can be rephrased into that csv is more specialised than json in representing tabular data. The fact that json can also represent tabular data does not mean it is a better or more efficient way to represent that data instead of a format like csv.
The reverse is true as well: being more specialized is a description of goals, not advantages.
In the same way, there are hierarchically structured datasets that can be represented by both json in hierarchical form and csv in tabular form by repeating certain variables, but if using csv would require repeating them too many times, it would be a bad idea to choose that instead of json. The fact that you can do sth does not always make it a good idea to do it. The question imo is about which way would be more natural, easy or efficient.