To be fair, that was also possible on some other 8-bit home computers of the time, but required the CPU to get involved (with tricky timing code to write the hardware registers at the right time). The 8-bit Atari's display list coprocessor is basically the daddy of the Amiga's Copper :)

Display lists date back to the antiquity of computer graphics, and Atari obviously knew how to build game machines.

Now we have GPUs which can do all sorts of things, but a graphics coprocessor for an 8-bit machine is a nice addition.