All I know is the tobacco does not have to acclimatize due to humidity, that makes zero logical sense considering that the tobacco is soaked in "stuff"(containing H2O). That liquid is going to flow in one direction and one direction only, out. Therefore you are essentially drying your tobacco since humidity will not flow into the tobacco, unless you live underwater. Water moves from areas of high concentration to areas of low concentration.
The only thing I see happening with this acclimatization "theory" he puts forth is just oxidation of the tobacco leaf itself and the components in the shisha. This will have a much larger effect in the flavor than the amount of humidity in the tobacco, considering the tobacco is soaked in what is essentially water.