What purpose do beer styles serve?

To my sort of incoherent post on beer styles below (my health improves, but slowly), Ethan John poses the right questions:
I guess I don't understand what the problem is. That it's harder to be a beer judge now? What negative consequence can more formally recognized styles possibly have?
Or, put another way, what purpose do beer styles serve? Certainly, when Michael Jackson began compiling books about world beer styles, there was a taxonomical purpose. In the 1970s, beer was at a low point of industrialization and consolidation, and the extant styles (some had actually died out) had been around for decades or centuries. He created an ethnography of beer, tracing the influence of history, regional climates and characteristics, and local ingredients in creating these styles. It was particularly useful for introducing the world to the full range of beer styles so that we had a sense of what existed and why.

The Brewers Association has essentially followed this model, forever adding styles every time a brewer does something different. The critique I have of their practice and methodology is that a) the new styles are now removed from the "ethnographic" context--adding coffee to a beer hardly creates a style as distinct and revolutionary as Czech brewers figuring out pale malts, b) the resulting categories aren't styles so much as ever sprawling categories of ingredients.

The result, rather than adding clarity to our understanding of beer styles, confuses it. In my earlier post, I used the example of a strong ales. There are now a whole raft of categories for what I would call a single, distinct style:
  • British origin: Other Strong Ales or Lagers
  • Imperial or Double India Pale Ale
  • Wood- and Barrel-Aged Strong Beer
There are actually more, like double red ales and barley wines and other high-alcohol beers. Distinguishing between the ones aged in wood and the ones aged in stainless is a distinction without a difference. It is also the case that the beer world is now international. I find the distinction between American-style ales and British-style ales wholly useless. There are regional variances between a Cascade-hopped NW pale ale and a Goldings-hopped London pale, but these do not constitute separate styles. In cooking, we wouldn't call a stew something else just because it didn't have potatoes.

And finally, distinguishing styles based on ingredients--there are a whole batch that exist only because of a single ingredient. But is a coffee stout remotely similar to a coffee schwarzbier?

If I were to play armchair psychologist, I would say we have this sprawling list because Charlie Papazian, a scientist, finds order in categories. Styles are an art, though. The purpose of having them at all is to bring coherence to a vast diversity of beers--not to merely create a name for every single variation.