Correct. But especially if you're using long cables a cable with more "headroom" in the eye diagram will perform more reliable than one that is just at the edge

Correct. But especially if you're using long cables a cable with more "headroom" in the eye diagram will perform more reliable than one that is just at the edge of breakup. For home use that doesn't matter usually, but I for example run events where I need the cable to work also after 10 people stepped on it and then this can become a significant thing. Not in terms of quality, but reliability.