> TFA claims the GeForce 256 was "the world's first GPU", but why not consider the NVidia Riva TNT a real GPU?

GeForce 256 integrated hardware vertex processing (transform and lighting), which Riva TNT and others did not - the CPU had to do this part.

The RCP of the Nintendo 64 was probably the first modern GPU integrating RSP for vertex processing and RDP for rasterization into a single chip.