Its an interesting case study in planned obsolescence, the radioactive half life being only a hundred days the anti-static effectiveness of the brush would completely disappear a couple years after manufacture, requiring the purchase of yet another brush.

Electronic / ham radio people would sometimes use staticmaster brushes in the winter when soldering RF preamp FET transistors to try and eliminate transistor-destroying static charge; I was never personally a believer in that technique at least at the amateur level.