There is a great importance of seeing oneself as one is. One of the key features of man is his rationality. It is one of the distinctive trademarks of man compared to the rest of creation.
It is important for man to realize that he is not fully rational however. If man understands his origin he will understand that he has fallen and his nature has been damaged by the fall - in particular his alienation from God.
If we understand that we often do irrational things it is helpful. A wise saying from a non Christian figure is that insanity is repeatedly doing the same thing and expecting different results.
Wisdom is not knowing all the answers. Actually wisdom often is knowing that we do not know the answers.
What people do not know is often not very dangerous to them if they know they do not know. What is dangerous is what people think they know but they are in fact wrong about.
One great think about understanding oneself as semi-irrational is that we can open ourselves to learn. Mostly from God, but also from others.