It's not a GPU. Back in the day (like 30 years ago) something like this might get slotted into a CPU as an accelerated math unit or a co-processor to a CPU to help with certain math functions. Interesting project but far away from what it is being reported as. Same applies to the CPU article which design was even further away from a CPU than this design is to a GPU.
Yeah it doesn't seem like much of a GPU, it has 4 compute units with 4 processors each and nothing seems specific to graphics. Like you say it seems much more like a maths accelerator.
It's also going to be very limited with only 11 instructions.
I can't help but feel that this guy is rushing it. First a CPU in two weeks and then a GPU in two weeks and neither is that good. He has likely missed a lot of things and made quite a few bad design choices. In my opinion it would be better to have taken more time and done more research to produce a better CPU from the start rather than rushing through a pretty bad design and calling it done.
He would also likely learn more by slowing it down, like learning the best design practices rather than pushing through with bad design decisions.