> The main issue is that a reader might mistake Redis as a 2X faster postgres. Memory is 1000X faster than disk (SSD) and with network overhead Redis can still be 100X as fast as postgres for caching workloads.

Your comments suggest that you are definitely missing some key insights onto the topic.

If you, like the whole world, consume Redis through a network connection, it should be obvious to you that network is in fact the bottleneck.

Furthermore, using a RDBMS like Postgres may indeed imply storing data in a slower memory. However, you are ignoring the obvious fact that a service such as Postgres also has its own memory cache, and some query results can and are indeed fetched from RAM. Thus it's not like each and every single query forces a disk read.

And at the end of the day, what exactly is the performance tradeoff? And does it pay off to spend more on an in-memory cache like Redis to buy you the performance Delta?

That's why real world benchmarks like this one are important. They help people think through the problem and reassess their irrational beliefs. You may nitpick about setup and configuration and test patterns and choice of libraries. What you cannot refute are the real world numbers. You may argue they could be better if this and that, but the real world numbers are still there.