[zaarn]

Schemaless definitely has a few applications, usually systems related to tagging. Luckily you can easily integrate schemaless into your Postgres database with no performance downside all thanks to the magic of JSONB or FDW, depending on which way you swing.

The very few pure schemaless databases that continue to exist and where I'm convinced they will continue to exist for a long while are those that specialize a lot (ie, Redis, Elasticsearch, a lot of the Timeseries databases).