There two different sports with two different sets of rules. Both have their moments of greatness or crappy performances (personal note; I like boxing better than MM). And each has a bit of an advantage over the other, giving the benefit of good fighters in each sport.
If wanting to get serious about fighting and use the black flag rules (actually no rules), than bare knuckles & no supports of any kind. Elbows/forearms, eye gouging, groin strikes, biting, foot stomping, finger breaking, nut grabbing/twisting, throat crushing , etc, etc, etc.....If someone wants to get it on, than get it on with no exceptions. The do in bars, alleys and in the street. Not to mention prisons.
Remembering back in my jr high school days when the Gracie family was dominating....slower than watching grass grow. Karate, and what passes for Kung Fu, etc, totally ineffective in real fighting. Great for the glory of a match in their own dojo...other than that useless. Good physical exercise though.