All of these points are valid, when given a caveat of "if Postgres covers your actual needs". Like, I've personally worked on many systems that used Redis for

All of these points are valid, when given a caveat of "if Postgres covers your actual needs". Like, I've personally worked on many systems that used Redis for absolutely no reason. As it was not actually measurably improving the latency of any part of the system. It was basically just another place to store data. Obviously, Postgres and Redis are not the same, and there are situations where keeping data in memory at all times is important for latency. Hence the caveat. But most companies are not in any such situation. Same story with the rest of these technologies - people often reach for them without really considering whether they are any sort of improvement over just storing the data in a relational database. This is commonly done by engineers who underestimate the capabilities of a relational database.