this is more a question of if you wanne embrace graphql
usually you would try and model your data in a relational model
graphql will then spit it out in hireachical json
so no need to store it hierachially
storing json should be your last resort
as the json itself cant be queried by graphql
in my eyes the only use case that cant eb prevented is when migrating an app and the json structure is different than what grapql can output.
but if you are building from scratch why not embrace grphql all the way through and unify your data handling