Specifically because it did transformation and lighting calcs in (non-programmable until GeForce 3) hardware, instead of in software on the main CPU.
Yes, NVIDIA made 3D accelerators before the GeForce line. I have many of them in my collection. But (IIRC) it did not market them as “GPUs”. That term wasn’t really used yet.
There were many periods in the 80s and 90s where console graphics hardware was kinda ahead of (even high-end/enthusiast) PC graphics hardware in certain ways that mattered for games of the time. Hasn't really been the case for a couple decades now, I guess.
Really the PS3's only saving grace was it was a great deal for a Blu-ray player.
I think the term you're looking for is fixed-function hardware.
But thank you for condescending anyway.
The NV1 and other cards before the GF256 did accelerated drawing and geometry raster but lighting and transformations were done on the CPU in main memory then transferred to VRAM and rasterized.
Even if the GF256 had say the same texel output performance as a TNT2, the T&L running on the GPU would allow for more complex scenes at higher frame rates than a TNT2 doing T&L on the CPU. The GF256 also had better raster performance so for many games it was just a "free" performance upgrade over a TNT2.