As the article comments, ROMs are not just bit-identical copies of the cart chips, but also contain various header metadata and eccentricities of how they're formatted based on what dumping tool you used, which exact cart, etc, and this one verbatim matches one found online.

Even in the cartridge days, game-devs still worked on patches and improvements for later publishing runs, so there can be many different versions of a cartridge game - and maybe the devs might have had even more recent builds of games that never got published because the publisher ended the run - so it's odd for Nintendo to go for the 'easy' route of repackaging an arbitrary version found online, compared to going through their own archives for something more recent, and presumably, of higher quality.

Sure, Nintendo make several versions of each cartridge. But they've all been dumped and put on the internet. Whichever version Nintendo chooses to release in their new emulator, it'll already have been dumped by someone else years before.