and parsing CSV is likely 10x faster than JSON :)
JSON parsing 10x faster than XML parsing | SQL Server Database Engine Blog
"Usually, when people talk about the performance of JSON in SQL Server, they are starting with “JSON is not actually a native type, it is just a plain text” and imply that it is probably too slow. It is true that JSON is stored as NVARCHAR and that there is no special type like for XML or Spatial. However, it does not imply that performance is worse than performance of full-blown types.
...parsing JSON plain text might be 10x faster than using native types."