"Just"

This is some serious black magic, especially if it actually works. Even if it only works some of the time I give it an A for effort, since they could easily have just said "JITs will not work with Rosetta." Most applications do not contain JITs.

My guess is there are enough important Mac apps that contain JITs of some form to merit this work, probably high performance math and graphics kernels that JIT processing pipelines or something like that. I wonder if some pro studio editing applications do this.