No, the piracy part come in when that dumped game is distributed, and guides are made so even the most computer illiterate people are able to play Nintendo games free of charge.

Personally, I don't think an emulator or ROM dump should be banned. However, I cannot deny that these exist primarily to pirate games. In the long run, I think paying customers will feel stupid for spending money when other people aren't so they'll stop too. Eventually, it will get to a point where Nintendo can't make a profit.

I think if you love the games, which I personally do, the moral thing to do is pay so that those games can continue to be made. But that's my moral, not legal, assessment.