But the "interface" to the JSON data is different than regular columns, and arguably awkward. The dynamic relational assumption is that one can use regular SQL just like with regular "static" tables (with some minor differences to make compare-type more explicit).
I find SQL much more awkward than proper language-idiomatic APIs.
Yes, SQL shines when you can whip up a big multi-table join, with nice group by-s and wheres, havings and whatnots, but that's rare. Though, arguably, ORMs solved most of the crazy string concatenation query crafting craziness.