lady who did the tour suggested a bit of water. Now, how does that differ from an ice cube?

Captain, the difference is this:

Water - particularly a little spring water at the same temperature as the malt - can bring out the flavour of the malt.

Ice deadens the flavour and kills the aroma - no harm, I suppose, for a blended whisky mixed with a dry ginger, but not good for an expensive malt.

You Yanks may well prefer drinks cold, on the whole, but not all drinks taste good when cold. Would you drink a good red Burgundy or Bordeaux wine which had been chilled? If you do, you're killing all the flavours of the wine. Your choice - and your taste loss.