I have found many use cases in our OLAP queries for BRIN indexes, as they are much much smaller and have comparable speed in the same order of magnitude as BTREE indexes.
Typically I use BRIN indexes for monotonically (or close to that) increasing timestamp columns. In our OLTP databases they are closely placed on the disk since naturally they get sequentially written as time goes.
In our warehousing Postgres instance some parts of the tables are loaded in big batches not necessarily ordered by time.
Is there some analytical query which would tell me if the data is placed too randomly to use BRINs even if seemingly the column value distribution should follow all the prerequisites for creating a BRIN index?