I know such miracles are not important to you (it seems Baha'u'llah couldn't/didn't perform any) but according to your own teachings belief in the possibility of such events is nothing irrational.
The operation of miracles is not necessarily irrational or illogical. It does by no means constitute a limitation of the Omnipotence of God. The belief in the possibilities of miracles, on the contrary, implies that God’s power is beyond any limitation whatsoever. For it is only logical to believe that the Creator, Who is the sole Author of all the laws operating in the universe, is above them and can, therefore, if He deems it necessary, alter them at His Own Will. We, as humans, cannot possibly attempt to read His Mind, and to fully grasp His Wisdom. (Shoghi Effendi, Lights of Guidance)
The appearance of other miracles, which have been attributed to the prophets, should not be categorically denied, because human reason is not the balance. (Baha'u'llah, Tablet of the River)
The same "arrogance" is in the belief that Baha’u’llah is the only messenger for this age and only his interpretation of all other sacred scriptures is valid.