I think the argument is really about transferablilty of skills. I already know how to manipulate compressed files because I have to do that in other places. And once you realize logs are just text files, I can immediately transfer all my skills of dealing with text files to dealing with logs.

But now I have to learn another set of tools (or at least another command to convert it to text files). It's not really a huge issue (I'm not really a systemd hater), but there can be a bit of dread when all the tools move off of standard formats, like simple text files, to custom formats, requiring you to learn idiosyncrasies of lots of different packages.

(And the reverse is true. Knowing how to use journalctl only helps me with systemd, and nowhere else. It's a piece of knowledge helpful in only one area that I cannot transfer anywhere else)