A machine does not read pictures. It follows a stitch plan literally: needle down here, thread to there, next point, no interpretation and no judgement. So the generator's output cannot be an image. It has to be an ordered path, the exact sequence a needle traverses to lay the design in thread.
That constraint is doing real work. Embroidery is a manufacturing step with physical rules, and a design that looks right on screen but cannot be sewn is not a design, it is a drawing. The stitch path is machine-stitchable by construction: the engine emits the ordered path directly rather than producing a shape that someone then has to convert into stitches by hand.
This is where the project keeps contact with the ground. The measure of the output is not whether it renders nicely, it is whether a machine can run it and whether the same seed produces the identical path every time. Both are checked end to end, so a claim of reproducibility is something the pipeline demonstrates rather than something it asserts.