Why do you need postgres, if you can get away with Redis? For all the 3 points mentioned in the article, I would rather just use redis as apposed to postgres. Unless, you really need a rds solution for the project.
>>ram_ra+(OP)
I think the article is assuming you already have Postgres for data storage and arguing against the addition of redis when that is the case, for the given common requirements that typically calls for the addition of redis into the mix.