Two wine connoisseurs tried the wine from a big barrel in a village. One detected a note of iron. The other said he tasted a hint of leather. All the villagers laughed at what pretentious snobs they were. Then, as the barrel was drained, someone found in the dregs an iron key with a leather fob*
A burley has an actual distinct, recognizable flavor, as does a virginia or an Oriental, etc. These flavors change according to where the tobaccos were grown, how they were cured, cased, topped, cut, blended, and aged. If a reviewer has the taste and knowledge to detect such things and is willing to write it down, the review will be useful--but only to the reader who knows enough to understand what the reviewer is talking about. I think a lot of the honey-coated-autumn-leaves type language found in reviews is an effort to reach a reader who may not know what, say, an uncased white burley blended with Izmir would taste like.
*I believe the story comes from an essay by David Hume.