bruegger is correct, I see that you are a new member, adn this topic has been covered at length.
My reasons for owning scout rifles (one custom built remington, one steyr):
They are "Faster" to get from ready position to the shot that traditional rifles.
They are light and easy to carry.
They are short and easy to carry.
The scout type scopes allow two-eye-open shooting, which reduces the loss of depth perception and peripheral vision that accompanies traditional scopes.
A lot of the country that I hunt in is "thick", shots are under 150 yards, and the deer can appear and disappear pretty quick.
(while I use these guns for hunting, I also think that they would serve me well in a defensive situation. Several members of my PD's swat team are also looking into using the scout concept, as we have a pretty densely populated city, and the close range, two-eyes-open thing appeals to them as well.)