These attenuators, or ones you could make with a few resistors, are no different from the multiposition Attenuators costing several hundred dollars that some audiophiles prefer to pots for gain control, except that they are permanently set to one particular value of attenuation. Of course, switch contacts are also avoided. If you don't use an attenuator what will you use? Probably a pot in the preamp or power amp, and that ain't exactly perfect.
