What make judo unique?

Judo's primary application is martial sport, and unlike every other sport/art I've seen involving throws, Judo's primary throwing focus is to disrupt the opponent's balance or capitalize on his/her own disruption of balance before executing the throw. This is what enables smaller people to throw larger, stronger opponents, although in the sport all other things are equal and contestants are separated into weight classes (so there are limitations). Judo is still effective in real applications, as hitting the pavement off a good throw is usually a fight-stopper. As a sport, though, it has limitations for self-defense and is best complemented by other forms like boxing and kickboxing/muy-thai. Other arts also have merit, but should be trained as hard as Judo is.