I'm not defending AQ, but there is validity in filtering high frequencies outside the audible range as they could have negative effects in the form of EMC/EMI. This could affect the TV more than an audio system, but an audio system with very wide bandwidth could waste its efforts amplifying inaudible stuff
like from Class D amplifiers or switching power supplies or even nearby cell phones. I'm not sure how any recommendation should be given, Amir, for its primary function of surge protection, unless that is tested. You can't assume anything these days