I used buckshot when hunting with dogs near Beaufort SC. My dad was a pilot in the Marines and they used to allow dog hunting with shotguns on the airstation. Basically it was a dozen or so guys, most would sit in lawn chairs around the perimeter of a 10ac(?) patch of woods. The dogs go in, the deer run out, guys in lawnchairs shoot at deer as they run out. As the deer are running, the pattern of the buckshot has the advantage of not requiring a single projectile to the vitals, you have more chances. Benefit #2 is the buckshot does not travel as far or carry as much energy as a single projectile.
Just about any other circumstance, Id rather have a bow/rifle/slug but for this type of hunting buckshot was mandated.
EDIT: I talked about the logic behind the buckshot, but not the performance. The 2 deer I shot with buckshot went down in a hurry, also witnessed a handful of other deer taken (I only hunted maybe 4 or 5 times this way). The key I think is limiting range.