There s a difference: MySQL has specific a datatype for JSON aside from only having JSON-related functions working n strings, which has a few benefits:

* The JSON datatype guarantees the content is valid JSON

* access to fields can be faster even without dynamic/virtual columns

* since 8.0 there are special optimizations for doing partial updates, which means that not the full JSON data has to be rewritten on small changes https://mysqlserverteam.com/partial-update-of-json-values/