You're correct, honestly it seemed like Sony was expecting ALL the graphics work to be done on the SPU's. The whole design of the Cell Broadband Engine is basic

You're correct, honestly it seemed like Sony was expecting ALL the graphics work to be done on the SPU's. The whole design of the Cell Broadband Engine is basically one SMT PowerPC core (PPU) and a bunch of stream processors (SPU's). Considering their choice in an extremely weak GPU compared to the Xenos in the 360, a lot of games had to move a bunch of work off the GPU and write it for the SPU's instead (which were nowhere near as nice to work with, they couldn't just pull data from system memory without you passing a pointer to them that was translated to an address they could DMA from, and you couldn't just throw GL or RSX commands at them so you were stuck writing all the nitty gritty by yourself).