USK: Phoenix Wright holding court on Wii
While it's true that future Ace Attorney games will probably be on handhelds, the series has already been ported to PC, proving that someone within Capcom — and not necessarily anyone involved with actually making the Ace Attorney games — has no issue with porting the existing titles, which is extremely likely to be what is happening here. And this is the same Capcom that said that Resident Evil 4 would be a GameCube exclusive.
Our guess would be an episodic WiiWare presentation of the first Phoenix Wright. Or a mistake in the rating description.