Comment by ollin

Right! The 256 introduced hardware T&L, which was a great advance in capability (but harder to explain than "it's the first GPU"). From the same chapter [1]:

   It was incontrovertibly true that the GeForce 256 represented a significant advancement in traditional graphics capabilities, which by this point was typical and expected of every new chip generation Nvidia produced. It featured four graphics pipelines, allowing it to process four pixels at the same time. It also integrated a hardware transform and lighting (T&L) engine, which meant it could take on the calculation tasks essential to the moving, rotation, and scaling of 3-D objects.

    Those tasks were usually handled by the CPU; the GeForce 256 thus took even more computational burden off of the CPU and made the entire computer run faster.
    
    "By putting dedicated hardware to do that, you could suddenly process a lot more geometry and make much more interesting pictures," said former chief scientist David Kirk.
    
    The management team at Nvidia thought that this was far too technical to pitch to customers. The typical in-house naming formula of acronym and number wouldn't work. Nvidia needed something bigger to market its new product.
    
    "We had to find a way to position this product as a much better graphics processor for 3-D graphics than anything out there," said Dan Vivoli. "The chip is big. It has texture and lighting. We've got to charge a lot for it. We need to come up with a way to make sure how great this thing is." He challenged his product-marketing team to come up with something brilliant.

[1] The NVIDIA Way / https://www.taekim.com again