Do they mark the very nadir of the audiophile industry?
Almost... the sad part, IMO is that they have
competition. IOW there are other 'grounding boxes'.
I started hearing about these about 10 years ago. I didn't know what they were, but when I read the manual I didn't know what they were, but I knew what they weren't
So I did a survey, to which only a few responded. To participate the one being surveyed had to have a DVM and I asked them to do certain measurements. What I found was if the equipment in the system was actually properly grounded (for single-ended gear, this meant chassis and audio ground were not the same thing) with proper AC safety grounds. the owner was far more likely to hear little or no benefit from the 'grounding box'. But if the equipment was poorly grounded (meaning ground loops might be present or the equipment wasn't grounded at all) then the owners were more likely to 'hear' a 'benefit'.