Besides all the issues mentioned in https://phusion.github.io/baseimage-docker/ , the other key win is "local IPC", not localhost.

Remote calls are a source of many evils. That is why Unix Domain Sockets have been invented.

I am not particularly fond of .NET but this article explains the why's well: https://andrewlock.net/using-unix-domain-sockets-with-aspnetcore-and-httpclient/

I am far from Kubernetes SME, but AFAIK K POD's "system calls" are all over UDS.

My advice would be: Find your balance in the number of containers vs multiple processes in containers but be aware: You want UDS whenever possible.