The claim was, and it seems to be true, that with a little water, you can control the burn, but keep the warmth. It also liberates some flavor molecules from the alcohol. Alcohol has an affinity for water molecules and when it forms a bond, everything else gets turned lose. The trick seems to be to have something in there to be turned lose.
The other trick seems to be how much water to add. Some 12 year old that I have was bottled at 80 proof. Thats a lot of water already and is very drinkable with just a few drops, or none. But I have some 8 year old that was bottled at 96 proof and it takes a lot of water, 20 percent of a dram, to make a smooth, flavorful, enjoyable drink. Some from the same distillery that was aged 16 years bottled at the same strength, only takes a little water to be smoother and much more flavorful.
That made me thirsty.