People say "Arch makes you learn how Linux really works", but I don't think that's a good way to put it.
Arch teaches you about the most boring parts of how linux works: the specific idiosyncrasies and configuration minutiae of a ton of libraries and programs (GNU coreutils, systemd, udev, mesa, glib, X11, Xlib, xdg, dbus, etc.)
Arch will usually not teach you the really interesting "low level" things about Linux: How the kernel works, how threads are created, etc.
I'd say it teaches you how to use Linux. It's not the particular details of each config file, but the fact that there are config files, and where to look for them. By the end of an Arch install, you know at least 85% of how to manage your system, and wiki will take you to let's say 98%.
No it doesn't. But that's fine, it's not the point of a distro to teach you about interrupts and syscalls and all that nonsense, the point of a distro is to give you software to install. That said, Gentoo does do a good job of teaching you how annoying it is to try and figure out exactly which kernel options you need to activate to get a working system. I always run out of patience before I get it working, though (yes, I know about make localmodconfig).
Arch teaches you about the most boring parts of how linux works: the specific idiosyncrasies and configuration minutiae of a ton of libraries and programs (GNU coreutils, systemd, udev, mesa, glib, X11, Xlib, xdg, dbus, etc.)
Arch will usually not teach you the really interesting "low level" things about Linux: How the kernel works, how threads are created, etc.