Postgres JSON(B) falls nearly in the same category. Do not use Postgres as a key value store, use a KV store for that.
Postgres JSON is great for storing the original JSON data coming from external APIs and Webhooks, such as Stripe payments. But it's not a silver bullet and really not a first class citizen. SQL query syntax for JSON data is awful, non-standard and requires casting types, which defeats the purpose of schemaless. I believe Postgres JSON types solve a different use case: an app based on a relational schema that needs to store JSON structures eventually.
I don't recommend starting off your app basing it on Postgres JSON. Use the full relational Postgres instead and do it right from the start.
Postgres JSON is great for storing the original JSON data coming from external APIs and Webhooks, such as Stripe payments. But it's not a silver bullet and really not a first class citizen. SQL query syntax for JSON data is awful, non-standard and requires casting types, which defeats the purpose of schemaless. I believe Postgres JSON types solve a different use case: an app based on a relational schema that needs to store JSON structures eventually.
I don't recommend starting off your app basing it on Postgres JSON. Use the full relational Postgres instead and do it right from the start.