All kidding aside, if you are going to release bourbon at less than barrel proof and therefore be diluting it with water to bring it down to bottling proof why wouldn't adding the water to the barrel improve the flavor? It allows the water to pick up oak/char/bourbon flavor, additionally it increases the fluid level in the barrel thereby allowing more of the barrel surface area to come back into contact with the bourbon (due to shrinkage from evaporation).
Will it make a huge difference? Hard to say. My question is what is the temperature of the water they are adding? Is it ambient temperature? Colder? Hotter? Is it like adding a couple of gallons of boiling water to a cask to extract out the last bit of whisky locked in the wood? I'm not saying it's a vast improvement or difference but maybe it would be noticeable.