Or more practically, a great thing for hikers and campers, who need to go for days or weeks with as few changes of clothes as possible.
The old fashioned way to do this was to wear underwear wozen out of nylon and silver threads. This makes the underwear antiseptic and prevents odor buildup. It also prevents static buildup and shields against RF radiation. So geeks who fix computers in their underwear might also benefit :-)
Quite expensive, though, and I never saw silver underwear sold to anybody but fitness and outdoors buffs.