It's almost entirely marketing. One manufacturer does it and others feel obligated to follow suit because they obviously want to sell product. They don't want to get caught without a feature that is perceived as desirable by the consumer, even if it is ultimately detremental to the best sound quality.

A good example is the infamous "spec wars" of the 1970s where Japanese vied with each other to have the lowest distortion and the highest damping factor. The problem is that this was done with massive amounts of negative feedback which caused these amplifiers to sound hard and sterile, giving Japanese amplifiers a bad reputation that has not entirely been restored. But they just had to have the best specifications on paper, sound quality be damned.

The consumer audio field is rife with fads that come and go, along with massive amounts of mis-information and downright snake oil.

Outlaw is commendable for it's lack of hype and attempts to misguide consumers, but the fact is that even they have to bow to market trends in order to sell product.