Some time ago when I started to learn Linux I have tried a lot of different distributions. All of them had their quirks. Some were buggy. Some were slow. Some had extremely weird and bloated configuration systems. Imagine several layers of abstraction above plain standard configuration files when you have to learn everything basically from the beginning with a different distribution. For example on top of standard config files they may have some configuration system (like YaST in SUSE) on top of which the GUI sits (so 3 layers just to change the screen resolution). Many distros have their own "unique" way of configuring the system. And when something will brake you will have no idea where the problem might be. Is it a bug in the package or in some layer of configuration system or somewhere else? I understand that they try to make the system more user friendly. Well, every one has its own niche.
With LFS you just learn the configuration of basic packages once. The way that package creator intended. Plain text files and nothing more. As an additional bonus you have great performance and security because you only have the packages you need. Plus everything is optimized for your architecture. If you have ever used some distribution in a virtual machine on a slow notebook you know what I am talking about.
When I built LFS for the first time I did everything by hand. It was a very useful experience and a nice way to learn. Of course now I don't do it manually. You can use automated tools (jhalfs for example) which extract instructions from the book and do everything for you. I don't use any graphical environment so no need to build a lot of stuff beyond the base system.
Of course LSF has its own issues. Lack of package management is one of them. But if you like minimalistic and fast systems you should give LFS a try.