So, essentially, a computer can do a repetitive, algorithmic (laying out the transistors, etc.), verifiable (simulate it and see if it is working as expected) task faster than a human... as computers have been designed to do since the beginning... Also, it designed a i486-level CPU (with a RISC instruction set, so exactly what are we really comparing?). That's peanuts, nowadays, and it would not seriously hit issues like heat dissipation, synchronization, or even laying out the pathways due to quantum effects for low nanometer scale and high clock speed CPUs of today, and that impose serious constraints on CPU design. A whole different game.
It is still interesting, but I am getting a bit tired of the "AI scaremongering, humans are obsolete" headlines.