MT-Card is useless at this point. We can edit saves already, manually. Next, we have rxTools, which replaces most CFW solutions for O3DS, and soon for N3DS. As MT-Card doesn't support the N3DS, it doesn't have that advantage either.
It's collecting dust, and no one really cares about it to be honest.
Best case scenario, someone makes a plugin for rxTools that identifies and mounts flashcarts for .3ds loading. Else, it's garbage and antiquated.