Is this legal?

It’s definitely against Nintendo’s terms of service and if they wanted to they could take legal action against those who make financial gain from it/the game.

It's against Nintendo's TOS, so I think so? Not sure if they can press charges or anything

These websites are against the TOS for virtually every online game out there, but for everyone one that might get shut down another 2 will crop up. Chinese game farms aren’t going anywhere...

I can see devs for MMOs and competitive games actually trying to enforce these rules and stop people buying from these sites, however I’d doubt Nintendo would bother spending energy to stop people buying items, when there is no competition and no winning animal crossing, it really doesn’t matter to anyone else if someone uses these sites. Can’t pay to win if there’s no win.

People do it anyways tho, all over facebook