I often executed the following command and have always thought in my head "give me the logs for user httpd".
Wait a second. I don't have a user httpd, only apache. And upon looking at journalct's man, I now see that I have been mistaken.
If you happen to know why Apache (and/or Centos which happens to be the distro I am using) didn't elect to use the same name, I would be curious to know why, but I don't really expect an answer. I would, however, like to know if there are any reasons why one wouldn't want to use the same name for a daemon user and systemd units?