The point is that function is relevant, and it doesn't make sense to fail to discriminate between function in this case, when we don't call discreet shifters brake levers, and there are not only discreet brake and shift levers, but different types of shifters as well. If I say my shifters don't work, you don't know what I'm talking about-- barcons? down tube? twist?-- but if I say brifters, there is no question beyond which brand.