Some powders are marketed towards the target and varmint shooting crowd as providing the best accuracy. Look at names like 10X, Varget, and Benchmark. Are some powders more accurate for a given caliber in all rifles? Are the above powders manufactured to stricter tolerances to promote better accuracy, such as benchrest primers? Or is it all marketing?
Given the fact that Varget and Benchmark generally list for the same price as Hodgdon's other powders, I'm inclined to think it's all marketing.