When I was a kid in Montreal, my folks took me to many classical recitals at Place des Arts. The pianists wore tails - tuxedos with tails, the tail being that bit of cloth hanging down to mid-thigh in the back. Until, that is, I went to a concert by pianist Vladimir Ashkenazy in which he wore a suit. A plain suit! The performance itself wasn't plain at all.
In traditional martial arts (TMA), one usually wears a gi. Gi pants are really good to wear when fighting because they are so loose. But the top? The gi top makes a nice snapping sound when you demonstrate a punch. Not so much when you really punch while fighting, maybe because the range of motion is usually a little less or a little more than the ideal snap-inducing range (or maybe I'm just not listening for the snap because I have other things to think about at the moment).
In Brazilian Jiu Jitsu, the gi top provides opportunities for grabbing and submissions that don't exist - at least not in the same way - in no-gi competition.
But let's be honest: a gi is just a pair of pajamas. Comfy, even stylish, but not intrinsically related to combat. Which is why it drives me up a wall when martial arts instructors insist on their students wearing a gi, and further suggest that this reflects their high standards. In fact it reflects nothing of the sort. What it does reflect is an obsession with form over substance, with superficial trappings over inner strength.
Bruce Lee wore a track suit. According to his daughter, Shannon Lee, "He wanted to wear something that didn’t signal that he was affiliated with any particular style — he was instead representing himself and his own style." And here we get to the essence of the gi obsession: it is, like most uniforms, a vehicle of conformity.
There are those who believe that conformity is a good thing, and in particular that uniforms for school-children are a good thing. If you believe this, then I guess it makes sense to believe in karate uniforms too. I myself am not a great fan of conformity. In the military I suppose it is necessary. But martial arts schools are not military academies.
Now, I'm not against conformity per se. Obviously life requires a balance of conformity and individualism. We cannot be social creatures without some level of conformity. And this extends to clothing. Even the most individualistic style of dress will most likely still conform to certain assumptions, if only the structural basics.
But making martial arts students wear a uniform because it supposedly ingrains in them values and virtues is, in my opinion, just silly. The person you are is not a function of the pajamas you wear. Being a martial artist is an inside job.