Several reasons. One, it's hard to hide a gun the size of my USP .45, even on my large frame. Two, it's hot as heck out there. Three, I prefer not having to worry about whether or not I'm flashing, printing, or whathaveyou. Four, I'm vehemently pro-2nd amendment and I want to exercise that right while we still have it. Five, I prefer deterrence to tactical surprise as well. Especially since it's easier to draw from an open holster than from under my dress shirts.