This might have been said before, but:
I'm willing to pay full price for a digital download just for convenience. I'm pretty lazy and don't like switching carts out usually. That's originally why I got a DS flashcard...before I broke down and pirated. Still, for some games such as Animal Crossing, I don't want to have to switch it out all the time, or never be able to play a different game cause I'll play that too much. I don't usually sell my games anyways, so really the only thing keeping me from digitally buying all my future games is an account system such as PSN, so I could safely redownload the game even if my 3DS broke or something.