If the Manifestation only wished for people to know the truth of things, this could be achieved with a single Word. So I do not think the objective is our understanding. After all, does it change anything to know whether Huri and Dijnn are figurative or literal?
Within the treasury of Our Wisdom there lieth unrevealed a knowledge, one word of which, if we chose to divulge it to mankind, would cause every human being to recognize the Manifestation of God and to acknowledge His omniscience, would enable every one to discover the secrets of all the sciences, and to attain so high a station as to find himself wholly independent of all past and future learning.
God gives to each soul a priceless opportunity to recognize Bahá’u’lláh for His own sake, and not according to his own understanding. Since the mind can never know God, or even the nature of its own self (!), the heart is what is tested.
But I don’t mean this in the sense of blind faith. Imagine an explorer who believes something about the world around him, based on principles he discerns without certain knowledge – even when others tell him he is wrong – and who demonstrates his faith by acting on that knowledge. If the truth of things were clear from the outset, the beauty of such courage would never be.