I also did it 20 years ago, but I got a lot more out of it. As each piece went in, I looked at it and what it did, and understood it as part of the whole that was built at the end.

If you don't do it reflectively, and simply copy and paste command lines, then I agree, you're not going to get anything out of it.

As it was, I had to debug a few build issues here and there, with version drift; that too was educational.

The biggest thing to come out of it for me, apart from understanding the Linux boot process better and a greater appreciation for chroot, was getting comfortable with ./configure [options] && make && make install for installing software from source.

Same experience with Gentoo and Arch.

It's not an in-depth theoretical guide, true, but it is still an awesome introduction and source of muscle-memory.