There's a small amount of harm because Postgres doesn't currently support request multiplexing and so its wire protocol doesn't have any facility for it. This pushes other databases to inherit one of Postgres's few true weak points.
I think the comparison is more like "is having an ad-hoc semi-standard wire protocol built around the postgres one better than having none at all?" and I think the answer is yes.
But it's not like there's an authority making this choice for everyone. If you think something else is better then use it in your tools and push for it. Postgres is ancient, open source, widely used and adapted for many different use cases. I think those all make it hard to beat in just a practical "worse is better" type way, but I also think people saying "no. we can do better" is good too, esp when they demonstrate it.
https://www.postgresql.org/docs/current/libpq-pipeline-mode....