Genuine question because I like retro games, what is the point of 4k here? It's blocky pixelated Mario kart, is there mods to update textures or something?
It just looks clean. Lowpoly games benefit from running at high resolutions to a surprising degree. The better the art, the more it benefits from being shown with as little obfuscation as possible. There are texture packs and shaders available for popular old games, but even without them, it's often worth it to ramp up the resolution, even far beyond 4K. I've played some old games at ridiculous resolutions like 5k or more, eliminating even a hint of jagged edges. You can then add a touch of retro flair through scanline and bloom shaders.
I’m a bit in both worlds. I think that the split is at HD games. Up to SNES a CRT really makes things look as they were designed, but once you reach 3D games the low rez really feels like a limitation game designers had to deal with.
The textures themselves remain at their original resolution. But anything that was 3d rendered in the original console (like the karts and characters in Mario kart) will now have crisp lines. Additionally many emulators will support some form of texture scaling to make the original low texture stuff look marginally better. On a system like N64 it’s a toss up on looking significantly better. But on a PS3 emulator for example, since many environments are rendered in 3d, it’s a considerable improvement
It looks absolutely stunning in 4K no pixels in sight with HD texture packs and 4K 3D renders. Now for older gen’s like SNES your CRT is a definite win.