The goal of N64 emulators (generally) is to accurately recreate the behavior of the original console.
Conversely, there is a large crowd of people who just want to play SM64, OOT and MM with a bevy of "graphical enhancements" like 60fps, widescreen, texture packs, randomizers, etc.
For these people, the fact that these games originally ran on the N64 is practically irrelevant. In fact, it's a hindrance; The N64's graphical pipeline is cumbersome to emulate and actively stands in the way of modern 'enhancements.'
This project is more aimed at giving the games themselves modern treatments, removing the N64-centric aspects of the games from the equation entirely.
What interests me more about recompilation is it can produce very efficient binaries instead of having to emulate everything. And also makes it easier to add new features.
Hilarious proof: https://imgur.com/gallery/Xw4tN#FoRAGl7
The characters in Mario Kart 64 were like that too, they just prerendered a heap of different angles and inserted the appropriate one.
With recompilation we could change those things, but I'm not sure how much work it would be and how many people who care to play those games would want to alter them that much.
Early 3d games will always have those rough edges sadly.