The pair will take more interest in breeding. You have more checks as what the pair is doing. This point is very important, here comes your management and all your success in the future depends on this point. How many chicks reared in a year, weather the pair are good parents.
The rate of hatchability of eggs increases and broken eggs diminishes due to non interference of other pairs.
More control on producing a specific color. As the chances of mating with bossy style males stops.
The growth of chick tremendously improves as the parents give more feed.
Chicks get more independently start eating food as they are made available to them all the times.
In case of viral infection it could not spread as fast as in the case of colony system.
Chances of fights with other breeding pairs and jealously reduces a lot.