after a decade of systemd usage I've never once had to actually think about the format the logs are stored in, or where they're stored; journalctl is actually easier than using tail and cat
This may seem obvious to you, but I for one find filenames much easier to remember. Of course the logs are inside /var/log (and not anywhere else).
Moreover, with filenames, you can check your logs with a program that is independent of the program that produces it. Why implement the -f option on other programs when it is already implemented in tail?
More than once I've forgotten the name of some unit I wrote -- the same as I easily forget filenames for random services I've installed, and where I might have installed them. I can discover the service name by calling systemctl status, or I can just call journalctl with no arguments and pass directly to grep to find what I need, in whatever unit it's in.
Try that when you have log files scattered all around your filesystem.
You have to remember unit names. They're all just names.
As I've been trying to allude to, 90% of this is familiarity, not some objective "better".
systemd is centralized.
That's wonderful for you. For me, it is not.
Funny how people are different.