What does the concept of illusion have to do with our life in this world? How do we make use of it?

Even though we now know the world is an illusion, it is a very real world from the standpoint of our eye, ear, nose, tongue, and body. Because of this relative reality, we have to be responsible to our society, family, and company employees; we need to build a career and provide for our family. We have to abstain from destroying and harming life, from stealing and cheating, etc. Knowing everything to be illusory, we must nonetheless distinguish between right and wrong, good and evil.

~Depicted from Luminous Wisdom Book Series : The Significance of Buddhist Philosophy Today