Can you please source your statistics?
Tired and I cant find the article, but personally almost everyone I know who's game has been corrupted in some way has had the downloaded version, I think only three that I know of had a cartridge problem. Plus, there are plenty of other reasons for having a physical copy is so much better.
To name a few:
If your 3DS gets damaged beyond repair you will lose your game. They also reserve the right to disable the ability to download again at any time.
If your old 3DS is broken/lost/stolen you have to purchase another copy of all your games. All of the digital content is tied to the console itself (even though it shows up on your Nintendo account). You can opt to send in a broken 3DS for repair and regain your data that way. The charge is somewhere in the neighborhood of $100 USD for this service (unless you're under warranty).
Saving the game to an SD card does not make the game transferable. You can only transfer the game using the 3DS to 3DS transfer. Again, the game is registered to the console and not to the storage device.
Nintendo will not replace lost or stolen content. If you own a 3DS with hundreds of dollars worth of digital content and it is lost or stolen, you're out of luck.
Also keep in mind that in the future you may want to play NL. If you have a digital copy and it's no longer available to download you're out your money.
So yeah, I'll keep my physical copy, thanks.
EDIT: On another note, I was thinking earlier today when switching cases how nice it would be it the DS had a cover for the cartridge like the do for the SD slot. I mean.. they're pretty much just big SD cards with a game on them anyway, and the spring and lock mechanism in them is super easy to get pushed accidentally. I'm surprised they didn't think of that a long time ago with the system. I guess they figure the only time you put your DS in your pocket its either off or in sleep mode, but sometimes I just tuck it away quick to get on the bus or something.
Seems like common sense really....