I have to say Pokémon Ranch is pretty important for me. With every generation I try to create a living Pokedex (having one Pokémon of each species). But if I do this this generation I only have one and a half boxes left. So where am I supposed to store my team / the shinys that I catch, etc.? So I have to store my living Pokedex on Ranch and while I could use my original game, transfering the save to it every time I want to connect gets really frustrating. Ofcourse I could use my original game all the time, but I like to cheat now and then (I don't cheat anything big in Pokemon, but I like to walk through walls from time to time and don't have to walk the 50 steps to recharge my Pokéradar), besides the reason for having a flashcard in the first place is, that you don't have to carry 50 games around with you.
Furthermore, if you want the special Pokemon you get from time to time in the japanese version of Ranch, you need a japanese game. See why a flashcard might come in handy here?
Pokémon is a hughely popular game and I think most Flashcard producers underestimate how such connectivity could benefit them. For example I wouldn't think twice about buying a Cyclo if the Acekard2 had it.