I have used jsonb in production and it is plenty fast for general purpose workloads. If you need high performance, you will want to stick with a normalized schema, but in general jsonb is pretty slick and highly performant when compared with things like mongo.

With that said, if you are developing queries against jsonb, you should really try not to use it. Dumping denormalized data into a single blob is going to make your life really painful in a few years when you have giant piles of highly differentiated data. Postgres will happily let you do it, and I don’t know your use case, but think carefully about the tech debt you may be incurring by using this over the long term