panty hose keep away ticks and other nasty critters that attracted to your skin and groin areas when you are in a field (training or combat environment) for extended periods of time.
The only reason I have never wore them is because I have just never thought in enough time to get them when I need them. I know of guys who have used them, obviously not on a regular basis.
I haven't noticed if the ladies in my church where panty hose or not. Maybe I should go looking this Sunday!