If a huge and extraordinarily powerful and athletic man is tough and can scrap in a fundamental way, he’s very dangerous.
Fighting is movement. Any attribute that enhances movement is an advantageous component in an altercation. Be it speed, STRENGTH, POWER, coordination, balance, flexibility, etc.
Tremendous size hugely aids one’s formidabity from the aspect of defence, movement impact and the value in absorbing punishment.
Bodybuilding as a pursuit has zero to do with fighting SKILL, but the resulting, again, ATTRIBUTES, can enhance the efforts when in a fray.
The athleticism inherent in strongman-type athletes, especially, is a phenomenal attribute in combination with the monolithic strength and size advantage.
P.S. Yates was sucker punched.
P.P.S. “Rolling on the mat” with a BJJ practitioner isn’t a on-the-fly dust-up in, say, a gym or store.