Final Fantasy Crystal Chronicles: Echoes of Time started out as a DS-only game. The Wii version came out because it was a painless process to bring Echoes of Time to the console.
“The DS version was the original source code, we made a system that automatically generated the Wii version,” Mitsuru Kamiyama, Director of Echoes of Time, said at a CEDEC panel, as reported by Gpara.
The Wii version actually uses the same data as the DS version, but handles it differently. Here’s an example of how the two systems render the models differently.
Square Enix’s Pollux Engine and “precious Wii / DS logo” have only been used for Echoes of Time so far. Gpara teases don’t be surprised if you see it again. Square Enix has a ton of DS games. Are there any you would want to play on the Wii?