Yeah there is actually a scientific reason for this that iv read before. A Triathlete can usually breath while running but if you are wrestling or in an MMA fight your breathing gets disrupted pretty often and you dont truly get your breathing rhythm back until you are in the guard or standing and separated. Shorter bursts with less air intake require a different sort of Cardio. They have a term for this but im unfamiliar with it. Anyway its part of the reason people put their hands over peoples mouth to disrupt their breathing. And obviously it could mentally make them go in a panic (But unlikely if you ask me.)
The difference is that endurance sports like triathlon are good for your cardio base and aerobic endurance, in particular lung capacities and how much oxygen your blood can transport, but wrestling training has more influence on how well your muscles make use of that oxygen in your blood and how fast there is an overproduction of lactic acids. While triathlon is almost completely aerobic, fighting is both aerobic and anaerobic.