It's not, lotus is probably getting confused because there's an Actuon Replay compatible with 3DS that lets you use action replay FOR DS GAMES on the 3DS
There is no action replay that is able to be used with 3DS games as of yet.
Oh wow, I used to have an action replay for Wild World! I didn't use it for getting a billion bells.... or anything like that... I literally just wanted to be able to plant palm trees by the top of my town (like near the gate) and put flowers on concrete, and make paths lined with tree stumps. But not with New Leaf, we have so much more town customisation--just like I'd wanted! So there's no need for an Action Replay for me! Not that I think I'd get one again, anyways. Haha.
It's not, lotus is probably getting confused because there's an Action Replay compatible with 3DS that lets you use action replay FOR DS GAMES on the 3DS
There is no action replay that is able to be used with 3DS games as of yet.
As others have pointed out, this isn't even possible on the 3DS or New Leaf yet. Even if it was possible, we generally discourage use and discussion of these devices on here.