Appraise for the effort. But I do not know why anybody did this kind of tedious job. Isn't it enough to do with Verilog / VHDL to fully understand basic architecture of CPU?
With discrete logic, the design can be done on paper and with standard EDA tools, and you can prototype it and test and build it on your workbench, and all the signals are exposed so you can inject and probe signals with standard test equipment.
I like the discrete logic approach because it feels more tangible and it's fun from an electronics tinkering perspective. But the FPGA method is for sure gonna be faster and smaller and cheaper, you just have to do all the work in software.
Depends on the experience you want in your hobby project, I guess. :)