You don't need a co-processor for that. Final Fantasies IV-VI all used the 3D mode 7 effect for the overworld, making the effect more exaggerated when the playe

You don't need a co-processor for that. Final Fantasies IV-VI all used the 3D mode 7 effect for the overworld, making the effect more exaggerated when the player enters an airship. It's fairly trivial and inexpensive to use HDMA to adjust the (pre-calculated) parameters for each scanline. Super Mario Kart needed the co-processor for determining things like how to draw the karts depending on their position and distance from the player. Pilotwings used the same co-processor for similar things (essentially, tracking objects and perspective in 3D space).