If you actually try to understand what’s happening, I think it’s one of the best ways to learn how a system is composed, at least if you install manually. What’s a partition, file system, what does mounting do, chroots, you name it.
I don’t use Arch anymore but still think it’s a great distro to learn the basics while still having the luxury of new binary packages. Manual Arch install abstracts basically nothing away from you, for better or for worse.
Currently on NixOS, I’d say while its engineering is better overall, the things you learn there are much more distribution-specific or maybe concept-specific and often not applicable to other distributions.
I guess there are also probably ways to install e.g. Debian manually, I’ve never seen instructions for it though as there was always the focus on the installer, and frankly I’m not a big fan of apt and all. It always seemed to be much more convoluted than pacman plus it does a lot of stuff for you, whether you want it or not was my impression.
The vast majority of people want to start by using Linux, they don’t want an in depth lecture about Linux. It’s like making someone take a course on bicycles instead of letting them get on the bicycle.
It appeals to a very specific niche who are already familiar with Linux and want that in-depth lecture. It’s not a good approach for beginners, and it’s not a good approach for experimented users who just want to install Linux fast.
Hey, I never said this is what people want, just that it is in fact a transferrable skill. I wouldn’t recommend it to anyone just trying to get their machine running, but if you’re looking to gain some insight, is not the worst choice.
What I meant by [non] transferrable is that the process is so highly specific to Arch that it won’t benefit you on any other distro. You will learn to connect to WiFi on Arch but this will not help you connect to WiFi on Ubuntu or Fedora. The Arch process does not tell you which concepts are generic and which are not. At the end of the day you’ve learned Arch Linux, but not necessarily “Linux”.