A lot of modern jets are computer controlled and are unflyable by mere human reactions. I think the canard, by introducing an instability, allows the craft to be extremely responsive when you want to turn quickly. The computer's job is to suppress by counter-commands all the times the bird wants to turn on its own spontaneously.
The only problem is that I think there were older, pre-robotics aircraft that may have used the canard element, so my version is just a guess.