Re: Dumbing down
It depends a little on who is running, but not as much as your comment suggests. Let's consider the part where you'll possibly erase and partition one or more disks. Let's also say that you have something else running, for the sake of simplicity on another drive. When you get to the point in the installer where you specify where it is supposed to install to, which partitions it should use, and what it should create, how do you select that? For a lot of users, the GUI is the way that makes sense and anything else doesn't. CLI tools would just confuse them and mean they can't install the OS, so they won't use the OS, so developers who are targeting them won't build for the OS, and the OS is less successful than it could be.
But who cares about those lusers anyway. We don't need anyone who doesn't have at least two terminal windows as soon as they log in. We only need an installer that works for us. Great. I live in the CLI a lot of the time and I'm quite familiar with the tools to get information about and modify disks and partitions. So I run the CLI installer, it gets to the part where I specify that information and I ... well wait a minute. I would know what to do if I dropped to a shell and could start executing some commands, starting with lsblk. That shell isn't an available option right now because I'm in the installer. I don't have multiple windows, and if I exit this, I have to start from scratch again. So what happens is that I have to start an Arch environment, get a shell, find all the information I'll need during installation, write that down somewhere, then enter it during installation. At that point, why shouldn't I just script this; it will mean less risk of typos at any rate.
So who needs an installer. Anyone who uses a CLI installer is just dumbing it down from the script they should be writing. Amateur idiots, all of you. Is that approach helpful? A GUI installer is not dumbing anything down from a CLI installer, assuming they both let you do the same things. It's just presenting exactly the same options in a different form, and a form that may reduce complications, allow users to configure their installation more quickly, and attract others to using and therefore benefiting the software.