They don't do anything at all
I bought some small bearings the other day (sealed low friction, high precision) for $9 each and they asked if they were for a fidget spinner. I was like WTF is that?
Since then I have seen them 4 times in one week, this must be the yo-yo of the late 2010's
(they are for my roller skates - thanks work for the $180 worth of bearings)