The introduction of gloves to boxing changed its whole approach to bare knuckle confrontations, as the gloves got better and bigger the boxers could actually hit each other in the head without breaking their hands.
Boxers also took advantage of the large surface area of the gloves and started to use them in ways that would have been impossible with bare knuckles, for covering, parrying and blocking.
The introduction of bigger and better gloves and the Marquess of Queensberry rules (1867) changed boxing forever from the bare knuckle art of pugilism to the sweet science we have today, these changes affected distance, strategy and tactics that boxers employed in the ring.
Karate is still a bare knuckle discipline and still retains the principles, strategies and tactics that comes with bare knuckle confrontations.
The proof that traditional karate technique is for the bare knuckle arena can be seen in mma matches and the UFC.
Traditional karateka like Lyoto "The Dragon" Machida who utilises shotokan karate as his stand up game and other karateka like George St-Pierre-kyokushin, Semmy Schilt-kyokushin, Victor Belfort-shotokan, and many many others.
All these athletes have trained in karate for a long period of time and have used their karate knowledge and skills successfully in mma matches, all say that karate had a big influence on them and their fight game.
Some of the other traditional karate fighters in mma/UFC competitions are (from Wikipedia),
Antonio Carvalho (Shotokan)
Nick Denis (Kyokushin)
Maciej Górski (Shotokan)
Neil Grove (Gōjū-ryū)
Mark Holst (Shotokan)
Katsunori Kikuno (Kyokushin)
Yuki Kondo (Shorinji Kempo)
Shinzo Machida (Shotokan)
Andrews Nakahara (Kyokushin)
Jadamba Narantungalag (Kyokushin)
Gunnar Nelson (Gōjū-ryū)
Seth Petruzelli (Shitō-ryū)
Bas Rutten (Kyokushin)
Assuerio Silva (Shotokan)
Also check out SHERDOG - 30 successful karate fighters in mma
MMA Karate fighters video playlist by Hotora86
Some great articles here about the bare knuckle boxing guard and the karate guard or kamae
1. The karate "kamae" or guard (Part-1) by sensei Dan Djurdjevic
2. The karate "kamae" or guard (Part-2) by sensei Dan Djurdjevic
Championship fighting - Jack Dempsey talks about a form of kime.
Championship fighting - Jack Dempsey
Bob Fitzsimmons vs James J. Corbett Part 1 & 2
Below are some snapshots of bare knuckle boxing technique, the similarities to traditional karate technique are self evident.