Nowadays, I am a devops/infrastructure engineer, and I can say LFS is a core foundational experience that has let me be better at my job. I know deeper inner workings of a Linux distro and that strong foundation helps. Yes there is so much more to learn but having LFS in your back pocket of lifetime experiences is great.
I also think its a 1 and done kind of thing. I don't see a huge benefit of doing it again. Maybe for fun, in a VM while waiting for other things to finish. It is also much faster nowadays. Back when I did it, I had a 1ghz, 256gb ram machine, it took me days. I could probably go through it in a day casually with modern computing, and especially since I have a threadripper machine, sending 64 threads at the make commands im sure will get my 1 BU to be a very small number.
If you have a child that is interested in computers, tech, programming, etc. I highly encourage this activity. Could be a fun bonding activity too.