Doing all those calculations in hardware (the distinction the marketing was based on) seemed like a pretty big deal at the time, at least within the context of consumer PC graphics cards. (It had long existed in the high-end workstation space, SGI etc. but the workstation and consumer PC ecosystems were more separated than they are these days.)

Which is kind of funny because the 1996 N64 RSP was a programmable GPU with Hardware T&L.