There must be a reason for it. Turns out, there is. And it's not a Nintendo 3DS cash-grab.
In the most recent "Iwata Asks" feature on Nintendo.com, Mario creator Shigeru Miyamoto says he really wanted to see Hyrule in 3D and that switching out items in the game is easier and streamlined in 3D. But there was different motivation to remake the 1998 classic.
"There are various reasons," says Miyamoto, "but the biggest one is that at that time the polygon count and frame-rate were truly working at the tattered edge."
The other game Miyamoto mentioned is Star Fox 64, which is also getting a 3DS remake. The game also takes advantage of the 3DS's glasses-free 3D, giving players a sense of depth and, dare I say, space.