I'm in the opposite camp. I don't like NoSQL because of the flexible schema. I have to build tools to make sure my data is consistent or have error handling. Migrations ensure that whenever I pull down a version of the code, the database is in the right state.
I don't see too many use cases where having being schemaless is a good thing outside of infrastructure ease of use. If you want to store arbitrary data in a table, BJSON in postgres is very efficient and flexible in that regard, while allowing you to have a schema for the rest of the data (e.g. if you are collecting data you probably want a schema for things like name, email, timestamp, etc and then have a BJSON field to jam in whatever you need.)
Having worked in ERP, Ecommerce, Financial tech, and general SASS based tech stuff, I agree with you on the "not too many use cases where having schemaless is a good thing". In most cases it's a shortcut and an unnecessary tradeoff made by people to avoid the few technical issues like DB migrations (also, a solved problem in many ways as long as you don't attempt to reinvent the wheel). The only time I saw a good use for a NoSQL db was to store products in Ecommerce. Managing taxonomy and attributes was always a nightmare and everyone was constantly afraid of performance issues (being on Magento and battling the EAV system didn't help). It would have been great to have only the products being stored on a NoSQL instance and the rest of the data being on the traditional relational data store.
I don't see too many use cases where having being schemaless is a good thing outside of infrastructure ease of use. If you want to store arbitrary data in a table, BJSON in postgres is very efficient and flexible in that regard, while allowing you to have a schema for the rest of the data (e.g. if you are collecting data you probably want a schema for things like name, email, timestamp, etc and then have a BJSON field to jam in whatever you need.)