[rleigh]

This depends entirely on how you want to set up and run the system. For packaged versions running as a system service with a dedicated service user, this is absolutely correct. And I would argue, it's a pretty sensible default arrangement.

But... there's absolutely nothing prohibiting you from running initdb as a regular user and then running the main daemon with your credentials. You are then the database owner and superuser. This type of thing is really useful for integration testing. But it's potentially useful when you don't care about the multiuser aspect and just want to have it run.