The first thing that sprang to mind when I heard the word 'magnets' was those magnetic faces where you use a magnet to make beards with. I can't describe it for the life of me - this is what I mean:
Evolutionary biologist Richard Dawkins did a short video on YouTube channel 'Big Think', where he explained 'the importance of doing useless things'. His first example was algebra, which is a little more useful than the any 'useless things' I can think of.
He says: "There are many things humans do that don't contribute to individual survival. The possession of the kind of brain that is capable of doing those things contributed to individual survival in our ancestral past."
I'm basically interpreting that as 'every adult should have a magnet beard-making thing'.