DMP's president Tatsuo Yamamoto said the company, "had a very ambitious goal in the realisation of naked-eye 3D stereo vision, and video game console-style high-quality graphics rendering, whilst maintaining low power consumption."
My guess from this is that DMP probably already had a buttoned-up solution for integrating 3D stereo vision with their GPU, saving Nintendo the development costs and enabling this super-fast time to market for the 3DS, and that's probably why they went with it. I'd expect for version 2 they'd perfect something with a more conservative architecture.
Genetics explains why you look like your father, and if you don't, why you should.