For all those asking why the 3DS version has high res textures if the game is so low res, you're forgetting how video games work.
Higher resolution allows for better clarity overall, but due to it being a video game, the camera is not fixed. I can still see the detail in texture work at lower resolution, it just means you have to walk or move the camera/character closer to see the detail.
It's not useless to have high res textures in lower res games. It still makes old games great, but yes, it also means that when the game is higher res, it breaths new life into it. That's why I love the fact that my Steam library feels so fresh again after all games got upgraded to 4K via GPU upgrades.