Yes, you need root to grant capture permission to Postgres, but Postgres doesn't need to run as root. The main purpose is to easily ingest network traffic data into Postgres for further process. Yes we can use tcpdump to do the same thing, but that needs another tool to load data into Postgres.

Do you come to this site looking for old established tech to talk about?

I like old solid tech like Postgres, libpcap and etc. Putting them together with new tech like Rust and pgx is also fascinating.