i meant the smm2 player models in the 2d styles SMB1,SMB3,SMW the other 2 styles use 3d models for the players

Many reasons this isn't full 3D:
• It would take a lot more system resources to load and render a highly-detailed model.
• This model only appears in the background, so it doesn't need to be super detailed.
• The 3DS has a 3D screen, so any truly flat planes wouldn't look as convincing as a model with some 3D depth.
• The model is fairly small on-screen, so if the details were fully modeled, it would become a mess of flickering pixels because of all the small details.
• I bet many people didn't even know the model wasn't full 3D, which means it was well designed for its specific purpose.

The reason Super Mario Maker 2 is 2D is because you can have hundreds of objects on screen that can stack in multiple ways. The system would struggle to handle 100 fully-modeled, fully-rigged Hammer Bros throwing hundreds of fully-modeled hammers. Nobody who plays the game even knows they are 2D, so once again they created a clever, invisible solution to a difficult problem.

gen why does Nintendo make models js to make them 2d sprites on a plane and add one thing thats actually 3d another 2d plane ik is the players in the 2d styles of smm2 are js planes but animated

Because it's a model? The propeller at the bottom is fully 3D, and even though the actual car and Koopalings (and Bowser) are just a flat texture, there is a bit of a curvature to it.

how the FUCK is this here

That's actually really clever

wow I never would have realized this was a 2d texture