When to use PARTITION BY HASH?

Hi!

I was reading up on declarative partitioning[1] and I'm not sure what could
be a possible application of Hash partitioning.

Is anyone actually using it? What are typical use cases? What benefits
does such a partitioning scheme provide?

On its face, it seems that it can only give you a number of tables which
are smaller than the un-partitioned one, but I fail to see how it would
provide any of the potential advantages listed in the documentation.

With a reasonable hash function, the distribution of rows across partitions
should be more or less equal, so I wouldn't expect any of the following to
hold true:
- "...most of the heavily accessed rows of the table are in a single
partition or a small number of partitions."
- "Bulk loads and deletes can be accomplished by adding or removing
partitions...",
etc.

That *might* turn out to be the case with a small number of distinct values
in the partitioning column(s), but then why rely on hash assignment instead
of using PARTITION BY LIST in the first place?

Regards,
--
Alex

[1] https://www.postgresql.org/docs/12/ddl-partitioning.html