This is equivalent to collections that you might find in classic NoSQL database because they store each JSON document as a single entity and optionally create indexes on these documents. The only difference is CLUSTERED COLUMNSTORE index on this table that provides the following benefits:
Data compression – CCI uses various techniques to analyze your data and choose optimal compression algorithms to compress data.
Batch mode analytic – queries executed on CCI process rows in the batches from 100 to 900 rows, which might be much faster than row-mode execution.
I think it’s worth reading this in conjunction with Niko Neugebauer’s comments regarding strings in columnstore.