Don't look at the end destination, look at the journey to the destination

* Learn low-level details of a basic but real-world CPU

* Practice the brain gymnastic of programming an atypical Turing-complete computer

Your created new connections in your brain, put to use some of the old established connections. Having a machine spit-out the emulator would rob you of all that. Like, you can drive from A to B, but running for A to B can do you much good.