Much like how games from the Wii Shop originally worked, games downloaded from the DSi Shop can’t be run off an SD card. While a quick and dirty workaround addressed this for the Wii, DSi software remains chained to the onboard memory.
It would appear that while new digital software made available for the 3DS (such as 3DSWare and Virtual Console games) will be able to play directly off an SD card, DSiWare that you buy new on or transfer over to the 3DS still requires fridge storage. Thankfully, there’s more internal memory on the 3DS, but I’m sure players would prefer storage options.
Before you shake your fist at Nintendo for being backwards once again, read the details carefully. From what I gather, this is a result of the way DSiWare and the DSi Shop infrastructure work. Nintendo has its hands tied in that regard. Again, all other 3DS exclusives will have SD workability, so there’s no cause for any serious alarm.
The return of the mini-fridge [N-Sider]